The Plural of “Testes”: Grammar Rules, Examples, and Usage Explained

by

English is filled with fascinating and sometimes perplexing rules for forming plurals, especially when it comes to irregular and scientific vocabulary. One such term that often raises questions is “testes”, the plural of “testis.” Understanding how to form and use irregular plurals like “testes” is crucial not only for advanced English learners, but also for students, teachers, editors, and professionals in scientific and medical fields. Mastery of these terms ensures precision, clarity, and professionalism in both academic writing and everyday communication.

This comprehensive article will guide you through every aspect of the pluralization of “testis” to “testes.” You’ll learn clear definitions, explore grammar rules and etymology, see a wide range of examples, and practice with interactive exercises. We’ll also highlight common mistakes, provide useful tables, and answer frequently asked questions.

Whether you’re a language learner, educator, or a scientist, this resource will help you confidently use “testes” in your writing and speech.

Table of Contents

3. Definition Section

3.1. What Does “Testes” Mean?

“Testes” is the plural form of “testis”. In biology and medicine, it refers to the two oval organs in males that produce sperm and hormones, especially testosterone. The word testis comes from Latin, where it has the same meaning. In English, “testes” is used to describe more than one testis.

Etymology: The term testis (singular) and testes (plural) are both borrowed directly from Latin, preserving the original scientific sense.

3.2. Grammatical Classification

The noun “testis” is:

  • Countable: You can have one testis or two testes.
  • Concrete: It refers to a physical, anatomical object.
  • Specialized: Most commonly used in scientific, medical, and educational contexts.

Singular: testis
Plural: testes

3.3. Function and Usage Contexts

“Testes” is typically used in scientific, medical, and educational texts, but may also appear in formal discussions or casual conversations about biology or health.

Context Use of “testis” Use of “testes”
Anatomy Textbook The left testis is slightly lower than the right. The testes produce sperm and hormones.
Medical Journal A single testis was examined for abnormalities. The patient’s testes were palpated during the exam.
Educational Materials Each testis is contained within the scrotum. Both testes descend before birth.
Casual Conversation I injured my testis while playing football. He had pain in his testes after the accident.

4. Structural Breakdown

4.1. Irregular Plural Formation in English

Most English nouns form their plurals by adding -s or -es (e.g., cat/cats, box/boxes). However, some nouns, especially those of Latin or Greek origin, have irregular plurals that follow different rules. “Testis” is one such example, forming “testes” rather than “testises.”

4.2. The Latin Root and Its Influence

Latin nouns ending in -is often form plurals by changing -is to -es. This rule is seen in scientific and medical vocabulary imported from Latin:

  • testis → testes
  • crisis → crises
  • analysis → analyses

This pattern is preserved in English to maintain scientific precision.

4.3. Pronunciation Differences

The pronunciation of “testis” and “testes” differs both in vowel sound and ending:

Word Spelling Pronunciation (IPA) Pronunciation (Text)
Singular testis /ˈtɛstɪs/ TES-tiss
Plural testes /ˈtɛstiːz/ TES-teez

Note: The -es ending in “testes” is pronounced as -eez, not -iz.

4.4. Morphological Analysis

To understand the change from singular to plural:

  • Start with testis (singular: -is ending)
  • Change -is to -es (following the Latin rule)
  • Result: testes (plural: -es ending and pronounced -eez)

This process is consistent with other Latin-derived anatomical terms.

4.5. Comparison with Similar Latin Plurals

Singular Plural Example Sentence
testis testes The testes produce hormones.
crisis crises Several crises affected the economy.
analysis analyses Her analyses were thorough.
thesis theses Graduate students write theses.
axis axes The graph has two axes.

Pattern: Singular -is → Plural -es (pronounced -eez)

5. Types or Categories

5.1. Plural Forms in Anatomy and Biology

The standard plural of “testis” in anatomy and biology is always “testes”. Other forms such as “testises,” “testi,” or “testies” are incorrect and not used in professional contexts.

5.2. Pluralization in Non-Scientific vs. Scientific Contexts

In everyday speech, people may use the word “testicles” more often than “testes,” but “testes” remains the only correct plural for “testis” in both scientific and medical writing.

  • Layman speech: “testicles” (common), “testes” (less common, but correct)
  • Professional/scientific writing: “testes” is required

5.3. Comparison with Other Irregular Latin Plurals

Anatomical Term (Singular) Plural Form Example
appendix appendices Surgeons removed two appendices.
cortex cortices The cortices process sensory information.
phalanx phalanges The phalanges are bones in the fingers.
foramen foramina Nerves pass through several foramina.
testis testes Testes are essential for reproduction.

6. Examples Section

6.1. Basic Usage Examples

  • The testes produce sperm cells.
  • Both testes are located in the scrotum.
  • Doctors examined the patient’s testes.
  • Testes are part of the male reproductive system.
  • During puberty, the testes increase in size.
  • Some animals have internal testes.
  • The hormones released by the testes affect development.
  • Mammals typically have two testes.
  • The testes are sensitive to temperature changes.
  • Injury to the testes can cause pain and swelling.
  • The function of the testes is crucial for fertility.
  • Both testes descended normally during development.

6.2. Complex Sentences and Contextual Usage

  • The testes are responsible for the secretion of testosterone, which plays a vital role in male development.
  • Abnormalities in the testes may lead to complications in sperm production and hormone balance.
  • In some mammals, the position of the testes changes with the seasons to optimize reproductive success.
  • Researchers studied the effects of environmental toxins on the development of testes in amphibians.
  • Histological examination revealed that the patient’s testes were affected by a rare infection.
  • During the surgical procedure, both testes were carefully assessed for signs of disease.
  • The testes contain seminiferous tubules where spermatogenesis occurs.
  • Testicular cancer can originate in one or both testes and requires prompt medical attention.
  • The descent of the testes is an essential process in fetal development.
  • Hormonal feedback mechanisms regulate the activity of the testes in response to signals from the brain.
  • The researchers observed significant variation in the size and shape of the testes among different species.
  • Testes that fail to descend, a condition known as cryptorchidism, may increase the risk of infertility.

6.3. Contrast with Singular Form

  • The right testis is larger than the left, but both testes function normally.
  • If one testis is injured, the remaining testis can often compensate.
  • In some cases, only a single testis is present, while most individuals have two testes.
  • The doctor checked each testis for lumps and then compared the two testes overall.
  • One testis may develop differently, but the testes still produce adequate hormones.

6.4. Examples in Different Tenses

Tense Example Sentences
Present
  • The testes produce sperm.
  • Testes regulate hormone levels.
  • Both testes function properly.
  • The testes respond to hormonal signals.
  • Doctors monitor the health of the testes.
Past
  • The testes descended before birth.
  • Scientists examined the testes under a microscope.
  • The testes were exposed to cold temperatures.
  • Both testes developed normally during adolescence.
  • Researchers measured the weight of the testes.
Future
  • The doctors will monitor the boy’s testes as he grows.
  • Researchers will study how the testes react to new medications.
  • The testes will mature during puberty.
  • He will have surgery to correct the position of the testes.
  • Future studies will examine testes development in mammals.

6.5. Examples in Questions and Negatives

Type Example Sentences
Questions
  • Are the testes functioning normally?
  • Do both testes produce hormones?
  • Why are the testes sensitive to temperature?
  • How many testes does a typical mammal have?
  • Did the testes descend at birth?
Negatives
  • The testes are not visible in this ultrasound image.
  • His testes did not descend as expected.
  • Testes do not always function properly after injury.
  • There are no abnormalities in the testes.
  • Both testes were not affected by the disease.

6.6. Example Tables

Table 1: Singular vs. Plural Noun Usage in Context
Singular (testis) Plural (testes)
The left testis is swollen. Both testes are swollen.
One testis was removed. The testes were examined.
This testis produces sperm. The testes produce sperm.
A single testis was affected. All testes were affected.
His right testis is larger. His testes are different sizes.
Table 2: “Testes” in Subject, Object, and Possessive Positions
Position Example
Subject The testes are vital organs.
Object The doctor examined the testes.
Possessive The testes’ size varies with age.
Table 3: “Testes” with Different Verbs
Verb Correct Usage
are (to be) The testes are healthy.
have (to have) The testes have descended.
produce (to produce) The testes produce hormones.
contain (to contain) The testes contain tubules.
develop (to develop) The testes develop during puberty.
Table 4: Comparison Table with Other Irregular Biological Nouns
Singular Plural Example
testis testes Testes are glands.
diagnosis diagnoses Several diagnoses were made.
phenomenon phenomena These phenomena are rare.
alveolus alveoli The lungs contain alveoli.
bacterium bacteria Bacteria are microscopic organisms.
Table 5: Incorrect vs. Correct Plural Usage (with Explanations)
Incorrect Correct Explanation
testises testes Never add -es to make the plural; use the Latin form.
testi testes -i is not the correct plural ending for “testis.”
testies testes -ies is not used for Latin -is endings.
testes is testes are Plural subject requires “are,” not “is.”
the testes’s the testes’ Plural possessive uses an apostrophe after the s.

7. Usage Rules

7.1. General Rule for “Testis” Pluralization

Rule: To form the plural of testis, change the -is ending to -es → testes.

Why “testises” is incorrect: The ending “-is” in Latin-derived nouns does not take a regular English plural. Instead, it follows a Latin-based pluralization, resulting in “testes,” not “testises.”

7.2. Agreement with Verbs and Pronouns

  • Subject-verb agreement: “testes” is plural, so use plural verbs (are, have, etc.)
  • Pronouns: Use “their” and “they” for “testes.”

Examples:

  • The testes are healthy.
  • The testes have descended.
  • Their testes are normal.
  • The testes produce hormones.

7.3. Article and Quantifier Usage

  • Use the with specific testes: “The testes are examined.”
  • Use some, both, these, several with “testes”: “Both testes are present.”
  • Do not use “a” or “an” with “testes” (those are for singular nouns).

Examples:

  • Both testes are examined.
  • Some testes may not develop properly.
  • These testes produce more hormones.
  • Several testes were affected.

7.4. Prepositional Phrases

Correct use in phrases:

  • in the testes
  • of the testes
  • between the testes
  • from the testes
  • on the surface of the testes

Examples:

  • Sperm is produced in the testes.
  • The size of the testes can vary.
  • Nerves run between the testes.
  • Hormones are released from the testes.

7.5. Special Cases and Exceptions

  • There are no widely accepted regional or historical variants for “testes.”
  • Medical jargon always prefers “testes” as the plural of “testis.”

In informal conversations, “testicles” may be used, but it is a different word with a different etymology.

7.6. Table: Usage Rules and Examples

Rule Correct Example Incorrect Example
Pluralization The testes are healthy. The testises are healthy.
Subject-verb agreement The testes have descended. The testes has descended.
Article/Quantifier Both testes are examined. A testes is examined.
Prepositional phrase Hormones are produced in the testes. Hormones are produced in the testises.
Possessive The testes’ size varies. The testes’s size varies.

8. Common Mistakes

8.1. Incorrect Pluralization

The most common mistake is using “testises” as the plural of “testis.” This is incorrect. The correct plural form is always “testes.”

  • Incorrect: The testises are located in the scrotum.
  • Correct: The testes are located in the scrotum.

8.2. Confusion with Other Anatomical Terms

Sometimes, “testes” is confused with similar-sounding or related anatomical terms.

  • “Testicles” is a synonym but not the direct plural. Use “testes” for scientific and formal contexts.
  • “Testosterone” is a hormone produced by the testes, not a plural form.

Example:

  • Correct: The testes produce testosterone.
  • Incorrect: Testosterone are located in the scrotum.

8.3. Incorrect Subject-Verb Agreement

Since “testes” is plural, it requires a plural verb form.

  • Incorrect: The testes is located in the scrotum.
  • Correct: The testes are located in the scrotum.

8.4. Pronunciation Errors

The correct pronunciation of “testes” is /ˈtɛstiːz/ (TES-teez). A common mistake is to pronounce the -es ending incorrectly.

  • Incorrect: /ˈtɛstɪs/ (TES-tiss) – This is the pronunciation for “testis” (singular).
  • Incorrect: /ˈtɛstɪz/ (TES-tiz)
  • Correct: /ˈtɛstiːz/ (TES-teez)

8.5. Table: Correct vs. Incorrect Examples

Table: Correct vs. Incorrect Examples
Category Incorrect Correct Explanation
Plural Form The testises produce sperm. The testes produce sperm. “Testes” is the correct plural form.
Subject-Verb Agreement The testes is important. The testes are important. Plural subject needs a plural verb.
Possessive Form The testes’s function is vital. The testes’ function is vital. Possessive is formed with an apostrophe after the ‘s’.
Synonym Confusion Testicles is essential for reproduction. Testes are essential for reproduction. “Testicles” is a synonym, use “testes” with a plural verb.

8.6. Spelling and Typographical Errors

Ensure that you spell “testes” correctly in your writing. Common typos can lead to confusion.

  • Incorrect: Tests, Testis (when referring to more than one)
  • Correct: testes

9. Practice Exercises

9.1. Fill-in-the-Blank

Fill in the blanks with the correct form (testis or testes).

  1. The doctor examined the patient’s __________.
  2. Each __________ is responsible for sperm production.
  3. Both __________ must descend for normal function.
  4. The left __________ is slightly larger than the right.
  5. The __________ produce testosterone.

Answers:

  1. testes
  2. testis
  3. testes
  4. testis
  5. testes

9.2. Correction Exercises

Correct the following sentences if they contain errors.

  1. The testises are located in the scrotum.
  2. Each testes is responsible for producing sperm.
  3. The testes’s function is to produce hormones.
  4. The testis are vital for reproduction.
  5. The doctor palpated the testies.

Corrected Sentences:

  1. The testes are located in the scrotum.
  2. Each testis is responsible for producing sperm.
  3. The testes’ function is to produce hormones.
  4. The testes are vital for reproduction.
  5. The doctor palpated the testes.

9.3. Identification Exercises

Identify the correct sentence in each pair.

  1. a. The testes is important.
    b. The testes are important.
  2. a. Each testis produce sperm.
    b. Each testis produces sperm.
  3. a. The testises descended normally.
    b. The testes descended normally.
  4. a. The doctor examined the testis.
    b. The doctor examined the testes.
  5. a. The testes’s size varies.
    b. The testes’ size varies.

Correct Answers:

  1. b
  2. b
  3. b
  4. b
  5. b

9.4. Sentence Construction

Create sentences using “testes” in the following contexts:

  1. Describing their function.
  2. Discussing a medical examination.
  3. Explaining their location.
  4. Comparing them in size.
  5. Stating a medical condition.

Example Sentences:

  1. The testes produce sperm and hormones.
  2. The doctor palpated the testes during the physical exam.
  3. The testes are located within the scrotum.
  4. The left and right testes vary slightly in size.
  5. The patient’s testes showed signs of inflammation.

9.5. Multiple Choice

Choose the correct plural form of “testis” in the following sentences.

  1. The _________ are essential for male reproduction.

    a) testis

    b) testes

    c) testises

    d) testi
  2. The doctor examined both _________ during the check-up.

    a) testis

    b) testes

    c) testises

    d) testi
  3. Healthy _________ produce adequate amounts of testosterone.

    a) testis

    b) testes

    c) testises

    d) testi

Answers:

  1. b
  2. b
  3. b

9.6. Practice Table

Fill in the table with the correct forms.

Context Singular Plural
Sentence The __________ is healthy. The __________ are healthy.
Possessive The __________ function is vital. The __________ function is vital.

Completed Table:

Context Singular Plural
Sentence The testis is healthy. The testes are healthy.
Possessive The testis’ function is vital. The testes’ function is vital.

10. Advanced Topics

10.1. The Role of “Testes” in Scientific English

In scientific English, particularly in fields such as biology, medicine, and zoology, the term “testes” is used to denote the male gonads with precision and clarity. Scientific writing demands accuracy, and “testes” is the accepted plural form in these disciplines.

It avoids any ambiguity or informality that might be associated with other terms.

10.2. Latin Pluralization Patterns in Medical English

Medical English often borrows from Latin, and understanding Latin pluralization patterns is crucial for accurate communication. The “testis” to “testes” transformation is a common example of this.

Other terms following similar patterns include “appendix” to “appendices” and “foramen” to “foramina.” Recognizing these patterns can significantly improve comprehension and usage of medical terminology.

10.3. Historical and Regional Variations

While “testes” is the standard plural form in modern English, there are no significant historical or regional variations in its usage. The term has maintained its form and meaning consistently across different time periods and geographical locations.

However, in less formal contexts, “testicles” might be more commonly used, though it is still considered a separate term rather than a variant of “testis.”

10.4. Singular vs. Plural in Compound Terms

When using “testis” or “testes” in compound terms, ensure that the singular and plural forms are used correctly. For example:

  • Testis cancer (referring to cancer in one testis)
  • Testes size (referring to the size of both testes)
  • Testis biopsy (referring to a biopsy of a single testis)
  • Testes development (referring to the development of both testes)

10.5. Table: Advanced Latin Plurals in Medical Vocabulary

Singular Plural Context
Apex Apices The apices of the lungs.
Varix Varices Esophageal varices can be life-threatening.
Meninx Meninges The meninges protect the brain.
Femur Femora The femora are the longest bones in the body.
Glomus Glomera Carotid glomera are chemoreceptors.

11. FAQ Section

Q: Is “testicles” the same as “testes”?

A: “Testicles” is a synonym for “testes,” but it is not the direct plural of “testis.” Use “testes” in scientific and formal contexts.

Q: Why is “testises” incorrect?

A: “Testises” is incorrect because “testis” follows Latin pluralization rules, where the “-is” ending changes to “-es” to form the plural.

Q: How do I pronounce “testes”?

A: “Testes” is pronounced /ˈtɛstiːz/, which sounds like “TES-teez.”

Q: Can I use “testes” in everyday conversation?

A: While “testes” is technically correct, “testicles” is more commonly used in everyday conversation. However, “testes” is still appropriate and may be preferred in more formal or educated contexts.

Q: What if only one testis is affected?

A: If only one is affected, use the singular form: “testis.” For example, “The doctor examined the left testis.”

12. Conclusion

Mastering the plural form of “testis” as “testes” is essential for clear and accurate communication, particularly in scientific, medical, and educational contexts. By understanding the Latin roots, following the correct usage rules, and avoiding common mistakes, you can confidently use this term in your writing and speech.

This comprehensive guide has provided you with the definitions, examples, exercises, and practical tips needed to ensure correct usage.

Leave a Comment