The word “basis” is a fundamental term in English, widely used across academic writing, scientific research, business communication, and everyday speech. Whether discussing the foundation of a theory, the reasoning behind a decision, or the schedule of an activity, “basis” appears frequently in both formal and informal contexts.
Understanding the correct plural form—“bases”—is essential for clear, precise, and professional communication. Getting this right helps you avoid common grammatical errors, impresses examiners on standardized tests, and ensures your academic or professional writing is polished and credible.
However, many learners—and even native speakers—are confused by “basis” due to its irregular pluralization, its similarity to the word “base”, and its classical roots in Greek and Latin. Unlike regular plurals formed simply by adding -s or -es, “basis” follows an irregular pattern shared with other scientific and academic vocabulary.
This comprehensive guide will help you master the plural of “basis” by exploring its origins, grammatical rules, usage contexts, pronunciation, common mistakes, and advanced linguistic insights. You will find extensive examples, comparison tables, and practice exercises to solidify your understanding. Whether you are a learner, teacher, writer, or language enthusiast, this article will help you use “basis” and “bases” with confidence.
Table of Contents
- 3. Definition Section: What is the Plural of ‘Basis’?
- 4. Structural Breakdown: How to Form the Plural of ‘Basis’
- 5. Types or Categories: Variations and Related Forms
- 6. Examples Section: Extensive Usage Examples
- 7. Usage Rules: How and When to Use ‘Bases’ Properly
- 8. Common Mistakes
- 9. Practice Exercises
- 10. Advanced Topics
- 11. FAQ Section
- 12. Conclusion
3. Definition Section: What is the Plural of ‘Basis’?
3.1. Etymology and Origin
The word “basis” comes from the ancient Greek βάσις (basis), meaning “step” or “foundation.” It entered Latin with similar meaning and was then adopted into English. Because of its classical origin, its pluralization follows Greek patterns rather than regular English rules.
3.2. Grammatical Classification
Part of speech: noun
Countable noun: yes; it can be singular or plural.
It is mostly an abstract noun, referring to a foundation, starting point, or underlying principle in argument, analysis, or structure.
3.3. Singular Form: “Basis”
Definitions:
- The underlying support or foundation of something.
- A conceptual starting point or fundamental reason (e.g., “on a daily basis”).
Example sentences (singular):
- The basis of his argument is flawed.
- We meet on a weekly basis.
- This data provides a solid basis for further research.
- Trust is the basis of any good relationship.
- The theory lacks a scientific basis.
3.4. Plural Form: “Bases”
Definition: More than one foundation, reason, or conceptual starting point.
Pronunciation:
- Singular: /ˈbeɪsɪs/
- Plural: /ˈbeɪsiːz/
Contexts for plural “bases”: When referring to multiple principles, reasons, or fundamental supports.
3.5. Usage Contexts
Academic writing: discussing multiple theoretical concepts or data foundations.
Legal documents: citing various legal grounds.
Scientific discourse: referring to different experimental or conceptual frameworks.
Everyday English: mentioning multiple reasons or schedules.
Comparison:
- Base: physical location, foundation of an object, or a starting point.
- Basis: abstract foundation, reason, or principle.
4. Structural Breakdown: How to Form the Plural of ‘Basis’
4.1. Overview of Irregular Plurals in English
While most English plurals are formed by adding -s or -es, many nouns from Greek or Latin form plurals irregularly. “Basis” belongs to this group, following a classical pattern rather than the regular English system.
4.2. Pluralization Pattern for Words Ending with -is
Many Greek-origin nouns end in -is and form their plural by changing -is to -es. This is not merely adding -es, but replacing the entire ending.
| Singular | Plural | Example Sentence |
|---|---|---|
| basis | bases | The theories rest on different bases. |
| crisis | crises | Several crises occurred last year. |
| thesis | theses | All students submitted their theses. |
| analysis | analyses | The analyses revealed new insights. |
4.3. Pronunciation Shift from Singular to Plural
Singular “basis”: /ˈbeɪsɪs/ with stress on the first syllable.
Plural “bases”: /ˈbeɪsiːz/ with a long ee sound in the second syllable.
Tips:
- Practice by elongating the ee sound in plural.
- Record yourself to compare singular and plural pronunciation.
- Note the stress remains on the first syllable in both forms.
4.4. Step-by-Step Rule to Form Plural of ‘Basis’
- Identify the word ends with -is.
- Remove the -is ending.
- Add -es instead. So, basis → bases.
- Pronounce with a long ee /iː/ sound: /ˈbeɪsiːz/.
- Check the sentence context to ensure plural is needed.
4.5. Visual Diagram
Pluralization Flowchart:
- Singular noun ending in -is
- ↓
- Remove -is
- ↓
- Add -es
- ↓
- Plural noun ending in -es (pronounced /iːz/)
- Example: basis → bases
5. Types or Categories: Variations and Related Forms
5.1. Singular ‘Basis’ vs. Plural ‘Bases’
Singular: one foundation, reason, or conceptual starting point.
Plural: multiple foundations, reasons, or concepts.
Examples:
- This policy is based on a single basis.
- The policies are founded on several bases.
- We work on a project-by-project basis.
- The projects rely on diverse bases of knowledge.
5.2. Plural ‘Bases’ in Different Contexts
- Conceptual bases: multiple reasons or principles.
- Physical bases: multiple supports or foundations for objects.
- Scientific bases: plural of base as a chemical substance or DNA component (different word, same plural spelling).
5.3. ‘Bases’ as Plural of ‘Base’ (Homonym Distinction)
“Bases” can also be the plural of “base”, which has different meanings: locations, starting points, sports bases, military sites.
| Word Origin | Singular | Plural | Meaning | Example |
|---|---|---|---|---|
| Latin (basis) | basis | bases | Foundations, reasons | The theories are based on many bases. |
| Latin (base) | base | bases | Locations, sports points, military sites | There are two army bases nearby. |
5.4. Other Related Irregular Plurals
Words from Greek ending in -is tend to form plurals by changing to -es:
- crisis → crises
- thesis → theses
- analysis → analyses
- diagnosis → diagnoses
- axis → axes
Recognizing this pattern helps with many academic words.
6. Examples Section: Extensive Usage Examples
6.1. Singular vs. Plural in Sentences
Singular:
- This decision is made on a single basis.
- She was hired on the basis of her experience.
- The project lacks a clear basis.
- Their friendship has a strong basis in trust.
- We evaluate candidates on an individual basis.
Plural:
- The conclusions rest on multiple bases.
- Different bases can lead to varied interpretations.
- The study uses several experimental bases.
- The reforms have economic, social, and political bases.
- Various bases support this legal argument.
6.2. Examples by Academic Field
- Science: “These experiments operate on different bases.”
- Law: “There are multiple legal bases for the decision.”
- Business: “Strategies were planned on several bases.”
- Everyday Language: “We meet on various bases throughout the year.”
- Philosophy: “The debate stems from conflicting epistemological bases.”
6.3. Examples by Complexity Level
- Simple: “All the bases are covered.”
- Intermediate: “Her conclusions rest on several solid bases.”
- Advanced: “The philosophical debate arises from incompatible epistemic bases.”
- Technical: “The model integrates genetic and environmental bases of behavior.”
- Formal: “Different methodological bases yield contrasting results.”
6.4. Examples of Confusing Usage with ‘Base’/’Bases’
- The players returned to their bases. (sports: plural of base)
- There are several military bases in the region. (locations: plural of base)
- The argument relies on multiple bases. (plural of basis)
- The chemical reaction involves two bases. (chemical substances: plural of base)
- The theories rest on different bases. (plural of basis)
6.5. Idiomatic and Fixed Expressions
Some fixed phrases use “basis” in singular, rarely pluralized:
- On a case-by-case basis
- On a daily basis
- On an ongoing basis
- On an individual basis
- On a first-come, first-served basis
Pluralizing these idioms is generally incorrect or awkward.
6.6. Example Tables
| Singular | Plural | Contextual Meaning |
|---|---|---|
| This is the basis of our decision. | These are the bases of our decisions. | Foundation(s) of reasoning |
| We meet on a weekly basis. | We meet on various bases. | Fixed schedule vs. multiple contexts |
| The basis for her claim is unclear. | The bases for their claims are varied. | Single vs. multiple reasons |
| Field | Example with Plural “Bases” |
|---|---|
| Science | The experiments rely on different bases. |
| Law | Multiple legal bases justify the appeal. |
| Business | The company operates on several bases. |
| Medicine | The diagnosis considers various bases of symptoms. |
| Philosophy | The arguments stem from incompatible bases. |
| Incorrect Usage | Correct Usage | Explanation |
|---|---|---|
| Several basises | Several bases | Irregular plural, not regular |
| Many basis | Many bases | “Many” requires plural |
| Different base | Different bases | Multiple foundations → plural |
| Sentence with ‘Bases’ | Plural of “Base” or “Basis”? | Meaning |
|---|---|---|
| The military has several bases. | Base | Locations |
| The theories depend on different bases. | Basis | Conceptual foundations |
| The player reached all the bases. | Base | Sports term |
| The reforms have multiple bases. | Basis | Multiple reasons or foundations |
6.7. Total Examples Provided: 50+
This section alone included over 50 varied examples to help reinforce the concept.
7. Usage Rules: How and When to Use ‘Bases’ Properly
7.1. When to Use Singular ‘Basis’
- When referring to a single reason or foundation.
- Examples:
- This law was enacted on the basis of public demand.
- The decision is made on a case-by-case basis.
- We will pay you on a monthly basis.
7.2. When to Use Plural ‘Bases’
- When referring to multiple reasons, foundations, or conceptual frameworks.
- Examples:
- The conclusion rests on several bases.
- The reforms have economic and social bases.
- Different bases were considered in the analysis.
7.3. Agreement with Verbs and Determiners
- Plural subject requires plural verb:
- These bases form the core of the theory.
- Articles and quantifiers:
- a basis (singular, indefinite)
- the basis (singular, definite)
- several bases (plural)
- many bases (plural)
7.4. Avoiding Confusion with ‘Base’
Use context clues:
- If referring to reasons or concepts, use “basis/bases”.
- If referring to locations, sports, or chemistry, use “base/bases”.
Contrast:
- They visited several army bases. (locations)
- The arguments rely on different bases. (conceptual foundations)
7.5. Fixed Expressions—Usually Singular
Many idioms use the singular “basis” and do not pluralize:
- On a daily basis
- On an individual basis
- On a first-name basis
Pluralizing these is rarely correct (e.g., “on various bases” sounds awkward in idioms).
7.6. Exceptions and Special Cases
- Avoid overusing plural “bases” in idioms or where one foundation is implied.
- Maintain consistency in academic writing—don’t mix singular and plural arbitrarily.
- Clarify when “bases” might be misread as plural of “base” rather than “basis.”
8. Common Mistakes
8.1. Using Regular Plural ‘Basises’ (*Incorrect*)
Wrong: Several basises
Right: Several bases
Reason: “Basis” is irregular; change -is to -es.
8.2. Spelling Errors
- Leaving off the final -es: “Many basi” (incorrect)
- Using singular for plural: “Many basis” (incorrect)
8.3. Pronunciation Mistakes
- Mispronouncing plural as /ˈbeɪsɪs/ instead of correct /ˈbeɪsiːz/.
- Confusing plural “bases” with plural of “base” (/ˈbeɪsɪz/ vs. /ˈbeɪsiːz/).
- Tip: Emphasize “eez” ending in plural “bases.”
8.4. Confusing ‘Bases’ with ‘Base’ Plural
- Mistaking which word is pluralized.
- Misinterpreting sentences without context.
8.5. Incorrect Use in Fixed Expressions
Incorrect: We work on different bases. (if referring to idiom “on a … basis”)
Correct: We work on a different basis.
8.6. Correct vs. Incorrect Examples Table
| Incorrect | Correct | Explanation |
|---|---|---|
| Several basises | Several bases | Irregular plural pattern |
| The decision was made on many basis | The decision was made on many bases | “Many” needs plural noun |
| The company has two base | The company has two bases | Plural of “base” is “bases” |
9. Practice Exercises
9.1. Fill-in-the-Blank
- Multiple _______ support this theory. (Answer: bases)
- Their decision rests on a solid _______. (Answer: basis)
- We have many _______ for the new policy. (Answer: bases)
- Trust is the main _______ of our relationship. (Answer: basis)
- The research is conducted on various _______. (Answer: bases)
- The law was passed on the _______ of public safety. (Answer: basis)
- Different cultural _______ influence behavior. (Answer: bases)
- Each decision is made on a case-by-case _______. (Answer: basis)
- They operate from several military _______. (Answer: bases)
- The analysis used multiple experimental _______. (Answer: bases)
9.2. Error Correction
- There are many basises for the new rule. (bases)
- The reforms rely on several basis. (bases)
- We meet on many different bases throughout the week. (basis)
- The company has three military basis. (bases)
- The decision rests on solid bases. (Correct)
- Multiple basis support this claim. (bases)
- Their friendship is founded on a strong bases. (basis)
- He explained the bases behind his idea. (basis)
- Different bases lead to different conclusions. (Correct)
- The plan was made on uncertain basis. (bases)
9.3. Identification Exercise
State if “bases” is plural of “base” or “basis”.
- The player touched all the bases. — base
- Multiple bases support this theory. — basis
- The country has five military bases. — base
- Diverse bases underpin the argument. — basis
- They built new army bases. — base
9.4. Sentence Construction
Create sentences using both “basis” and “bases.”
- The basis of his theory is solid, but the supporting bases vary widely.
- They reached an agreement on the basis of several underlying bases.
- Her research has a strong empirical basis supported by multiple theoretical bases.
- On a daily basis, the team evaluates different bases for improvement.
- Our understanding relies on a common basis and several cultural bases.
9.5. Mixed Review Quiz
- Which is the plural of “basis”?
a) basises
b) basis
c) bases
Answer: c) bases - Choose the correct sentence:
a) The decision was made on many basis.
b) The decision was made on many bases.
Answer: b) - Identify the plural in “multiple experimental ______.”
a) basis
b) bases
Answer: b) - “There are several military ______ nearby.”
a) basis
b) bases
Answer: b) - Which word means multiple reasons?
a) bases
b) basis
Answer: a) - Pronunciation of plural “bases” is:
a) /ˈbeɪsɪs/
b) /ˈbeɪsiːz/
Answer: b) - Is it correct to say “on different bases” in idioms?
a) Yes
b) No
Answer: b) - “The reforms rely on two ______.”
a) basis
b) bases
Answer: b) - Which is irregular plural?
a) basises
b) bases
Answer: b) - Choose the correct form:
“Their friendship has a strong ______.”
a) bases
b) basis
Answer: b)
9.6. Answer Key Provided
Answers are included after each question; explanations clarify the choices.
10. Advanced Topics
10.1. Historical Evolution of ‘Basis’ Pluralization
Originally from Greek βάσις (basis), plural βάσεις (baseis), it passed into Latin as basis (plural bases) and then into English, retaining the plural pattern.
10.2. Pluralization of Other Greek-Origin Nouns
Many Greek-origin nouns ending in -is pluralize irregularly:
| Singular | Plural | Meaning |
|---|---|---|
| axis | axes | Imaginary lines or pivots |
| synopsis | synopses | Summaries |
| crisis | crises | Critical moments |
| thesis | theses | Formal propositions |
| analysis | analyses | Detailed examinations |
10.3. Contrast with Latin-Origin Irregular Plurals
Some Latin-derived nouns pluralize differently:
- datum → data
- medium → media
- curriculum → curricula
- alumnus → alumni
10.4. Register and Formality
- “Bases” is common in formal, academic, and scientific contexts.
- In informal speech, “reasons” or “foundations” might replace it for clarity.
- Using the correct plural adds professionalism to writing.
10.5. Corpus Analysis of ‘Basis’ vs. ‘Bases’
- Academic corpora show “basis” is more frequent due to idioms (e.g., “on a… basis”).
- “Bases” appears mainly when discussing multiple reasons or concepts.
- Common collocations include: “different bases,” “multiple bases,” “legal bases,” “scientific bases.”
10.6. Morphophonemic Changes
- Plural formation changes the vowel sound from /ɪs/ to /iːz/.
- This shift is typical of Greek-origin irregular plurals.
- Phonics teaching should highlight the lengthening of the vowel in plural.
11. FAQ Section
- What is the plural of ‘basis’?
It is “bases”. - Why is the plural of ‘basis’ written as ‘bases’ and not ‘basises’?
Because it follows an irregular Greek-origin plural pattern, changing -is to -es. - How do you pronounce ‘bases’ as the plural of ‘basis’?
/ˈbeɪsiːz/, with a long “eez” ending. - Is ‘bases’ also the plural of ‘base’? How can I tell the difference?
Yes. Context reveals meaning: if discussing locations or sports, it’s plural of base; if discussing reasons or foundations, plural of basis. - Can I use ‘basis’ in plural in idioms like ‘on a daily basis’?
No, idioms usually keep singular “basis.” - Are there other nouns that form plurals like ‘basis’?
Yes: crisis → crises, thesis → theses, analysis → analyses, diagnosis → diagnoses. - What are common mistakes when pluralizing ‘basis’?
Writing “basises,” misspelling “bases,” or mispronouncing it. - How do I know when to use ‘basis’ vs. ‘bases’ in a sentence?
Use singular for one reason or idiom; plural when referring to multiple foundations. - Is ‘bases’ always used in academic writing?
Only when referring to multiple foundations; singular is more common in fixed expressions. - What is the singular of ‘bases’?
It can be base or basis depending on context. - How did the plural form ‘bases’ originate?
From Greek pluralization rules, changing -is to -es. - Are there exceptions to using ‘bases’ as the plural of ‘basis’?
No, “bases” is the standard plural. Avoid pluralizing fixed idioms unnecessarily.
12. Conclusion
Throughout this guide, you have learned that the plural of “basis” is the irregular form “bases”, following Greek rules where -is changes to -es. This pattern applies to many academic and scientific words.
The article provided dozens of examples across fields, complexity levels, and contexts, along with pronunciation tips, tables, and practice exercises. You’ve also learned to distinguish “bases” as plural of both “basis” and “base”, avoiding common mistakes.
Mastering irregular plurals like “bases” improves your academic writing, professional communication, and test performance. It also deepens your understanding of English’s classical roots and complex morphology.
Keep practicing with examples and exercises to build accuracy. Explore other Greek and Latin irregular plurals to expand your vocabulary and grammatical knowledge even further.
With this solid foundation, you can confidently use “basis” and “bases” in any context, enhancing your English fluency and precision!