Common Mistakes with the Plural of Basis
If you are writing a business report, an academic email, or a professional memo, the word basis often appears. The most common mistake is treating basis as if it has a regular plural like basises. The correct plural is bases (pronounced BAY-seez). This guide explains the rule, shows you how to use it naturally, and helps you avoid the errors that even experienced writers make.
Quick Answer: What Is the Plural of Basis?
The singular is basis. The plural is bases. Do not write basises or basisses. The word follows the Latin plural pattern: crisis becomes crises, thesis becomes theses, and basis becomes bases. In writing, always check that your verb matches the number: the basis is (singular) or the bases are (plural).
Understanding the Singular: Basis
Basis means the underlying reason, principle, or foundation for something. It is a singular noun and takes a singular verb.
- The basis for our decision is the quarterly data.
- We need a solid basis for the contract.
- Her argument has no logical basis.
In business writing, basis often appears in fixed phrases like on a daily basis, on a case-by-case basis, or on a regular basis. These phrases are always singular.
Understanding the Plural: Bases
Bases refers to multiple foundations, principles, or starting points. It takes a plural verb.
- The bases for the two proposals are completely different.
- We examined several bases for the pricing model.
- Different projects require different bases of support.
Note: Bases is also the plural of base (as in a military base or a base in a hierarchy). Context tells you which meaning is intended. In business writing, the context is usually clear.
Comparison Table: Basis vs. Bases
| Word | Number | Meaning | Example |
|---|---|---|---|
| Basis | Singular | One foundation or reason | The basis of the agreement is trust. |
| Bases | Plural | Multiple foundations or reasons | The bases for the claims are weak. |
Natural Examples in Business Contexts
Formal Writing (Reports, Proposals, Policies)
- The basis for the new policy is the safety audit.
- We identified three bases for the cost reduction strategy.
- Each department operates on a different basis of funding.
Emails and Internal Communication
- Please send updates on a weekly basis.
- The bases for the budget changes are explained in the attachment.
- We need to agree on the basis for the partnership.
Conversation and Everyday Use
- What is the basis for your opinion?
- They have different bases for their decisions.
- We meet on a regular basis.
Common Mistakes with the Plural of Basis
Mistake 1: Using “Basises”
Incorrect: The basises of the arguments are flawed.
Correct: The bases of the arguments are flawed.
This is the most frequent error. English learners often add -es because it sounds natural. However, basis belongs to a small group of Latin-derived nouns that change -is to -es.
Mistake 2: Confusing “Bases” with “Base”
Incorrect: We need to cover all the base of the project.
Correct: We need to cover all the bases of the project.
Base (singular) means a physical foundation or a starting point. Bases (plural) can mean either multiple physical bases or multiple principles. In business writing, when you mean “multiple underlying reasons,” use bases.
Mistake 3: Using a Singular Verb with “Bases”
Incorrect: The bases for the decision is unclear.
Correct: The bases for the decision are unclear.
Always check subject-verb agreement. Bases is plural, so the verb must be plural.
Mistake 4: Overusing “On a Daily Basis” Incorrectly
Incorrect: We review reports on a daily bases.
Correct: We review reports on a daily basis.
The phrase on a daily basis is fixed. Basis is singular here because it refers to one routine.
Better Alternatives and When to Use Them
Sometimes basis or bases can sound formal or repetitive. Here are natural alternatives for different contexts.
| Original Phrase | Alternative | Context |
|---|---|---|
| On a regular basis | Regularly | Conversation, email |
| The basis for | The reason for | Informal writing |
| On a case-by-case basis | Individually | Business email |
| The bases of | The foundations of | Formal report |
| On a daily basis | Every day | Conversation |
Use basis and bases when you need precision and formality. Use alternatives when you want a more natural or less repetitive tone.
Formal vs. Informal Tone
Formal: The basis for the amendment is the revised financial forecast.
Informal: The reason for the change is the new forecast.
Formal: We operate on a quarterly basis.
Informal: We meet every quarter.
In emails to colleagues, you can often use simpler alternatives. In reports, contracts, or official documents, basis and bases are appropriate.
Nuance: When “Bases” Can Be Confusing
Because bases is also the plural of base, a sentence like “We visited the bases” could mean military bases or foundational principles. In business writing, the context usually resolves the ambiguity. If confusion is possible, rephrase:
- Instead of: “We reviewed the bases of the agreement.”
Write: “We reviewed the underlying principles of the agreement.” - Instead of: “The bases are in different locations.”
Write: “The physical bases are in different locations.”
Mini Practice Section
Choose the correct word: basis or bases.
- The ______ for the new policy is customer feedback.
- We identified several ______ for the cost increase.
- Please report on a weekly ______.
- The ______ of the two arguments are completely different.
Answers:
1. basis (singular, one policy)
2. bases (plural, several reasons)
3. basis (fixed phrase, singular)
4. bases (plural, two arguments)
Frequently Asked Questions
1. Is “basises” ever correct?
No. Basises is not a standard English word. The correct plural is bases.
2. How do you pronounce “bases” (plural of basis)?
It is pronounced BAY-seez. This is different from bases (plural of base), which is pronounced BAY-siz. The vowel sound in the second syllable changes.
3. Can “basis” be used as a plural?
No. Basis is always singular. If you need a plural, use bases.
4. What is the difference between “basis” and “base”?
Basis usually refers to an abstract foundation, principle, or reason. Base usually refers to a physical foundation, a location, or a starting point. Compare: “The basis of the theory is sound” (abstract) vs. “The base of the building is concrete” (physical).
Final Tip for Business Writers
When you proofread your work, search for the word basis. If you mean more than one, change it to bases and check the verb. If you are using a fixed phrase like on a regular basis, keep it singular. With a little practice, this common mistake will disappear from your writing.
For more help with tricky plurals, visit our Confusing Plurals section. You can also explore Common Plural Forms or Plural Spelling Rules for additional guidance. If you have questions, see our FAQ or contact us.
