basis

American  

[bey-sis] / ˈbeɪ sɪs /

noun

bases plural

1. the bottom or base of anything; the part on which something stands or rests.

2. anything upon which something is based; fundamental principle; groundwork.

3. the principal constituent; fundamental ingredient.

4. a basic fact, amount, standard, etc., used in making computations, reaching conclusions, or the like.

   The nurse is paid on an hourly basis. He was chosen on the basis of his college grades.

5. Mathematics. a set of linearly independent elements of a given vector space having the property that every element of the space can be written as a linear combination of the elements of the set.

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basis British  

/ ˈbeɪsɪs /

noun

1. something that underlies, supports, or is essential to something else, esp an abstract idea

2. a principle on which something depends or from which something has issued

3. maths (of a vector space) a maximal set of linearly independent vectors, in terms of which all the elements of the space are uniquely expressible, and the number of which is the dimension of the space

   the vectors x, y and z form a basis of the 3-dimensional space all members of which can be written as ax + by + cz

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basis Scientific  

/ bā′sĭs /

bases plural

1. A set of independent vectors whose linear combinations define a vector space, such as a reference frame used to establish a coordinate system.

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basis Idioms  

1. see on a first-name basis.

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Usage

Plural word for basis The plural form of basis is bases, pronounced [ bey-seez ]. The plurals of several other singular words that end in -is are also formed in this way, including hypothesis/hypotheses, crisis/crises, and axis/axes. A similar change is made when pluralizing appendix as appendices. Irregular plurals that are formed like bases derive directly from their original pluralization in Latin and Greek.

Related Words

See base ¹.

Etymology

Origin of basis

First recorded in 1525–35; from Latin, from Greek básis “step, place one stands on, pedestal,” from ba(ínein) “to walk, step” ( see also come) + -sis -sis; cf. base ¹

Explanation

Basis is the underlying reason or assumption. The basis of a dictionary is that people are curious to learn the meanings of new words. You are interested, right? Basis can also apply to a system or pattern that has been established. For example: Since your job is so exhausting, you need vacations on a regular basis. The basis of democracy is regular free elections. Not surprisingly, as its sense of something from which other things spring, basis comes from the Latin word of the same spelling meaning "foundation."

Example Sentences

“That sounds like you really have the basis for an agreement. … But don’t fool yourself to think that completely addresses the situation.”

From Los Angeles Times • May 23, 2026

"Therefore, there is absolutely no basis for claiming that the munitions struck the building as a result of our air defence or electronic warfare systems," the Kremlin leader said.

From BBC • May 23, 2026

Likewise, women connect more frequently with their friends on a weekly basis, whether through calls or texts, than men.

From The Wall Street Journal • May 23, 2026

Williams values EchoStar at $155 a share on a sum-of-the-parts basis.

From Barron's • May 22, 2026

The economic basis for the powerful Aztec state was hydraulic agriculture.

From "An Indigenous People’s History of the United States" by Roxanne Dunbar-Ortiz

Related Words

• assumption
• base
• essential
• evidence
• explanation
• footing
• fundamental
• justification
• premise
• principle
• proof
• reason
• security
• support
• theory