basis

American  

[bey-sis] / ˈbeɪ sɪs /

noun

plural

bases

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.

---

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

---

basis Scientific  

/ bā′sĭs /

plural

bases

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

---

basis Idioms  

1. see on a first-name basis.

---

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” ( come ) + -sis -sis; 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

The facility also would serve about 1,000 people on an outpatient basis.

From Los Angeles Times • Apr. 13, 2026

The report does state the vacancies are 6.4% of the total workforce on a whole-time equivalent basis.

From BBC • Apr. 12, 2026

Let’s proceed on the basis that you own your home outright.

From MarketWatch • Apr. 10, 2026

The two-year Treasury yield rose 1 basis point to 3.791%; the 10-year yield was up 0.6 bp at 4.298% and the 30-year yield edged up 0.3 bp to 4.900%, according to Tradeweb.

From The Wall Street Journal • Apr. 10, 2026

Conferences, strategy sessions, and debates regarding how best to build a movement to dismantle the new caste system would be occurring on a regular basis.

From "The New Jim Crow" by Michelle Alexander

Related Words

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