basis

noun

ba·​sis ˈbā-səs 

plural bases ˈbā-ˌsēz 

1

: the bottom of something considered as its foundation

2

: the principal component of something

Fruit juice constitutes the basis of jelly.

3

a

: something on which something else is established or based

stories with little basis in reality

no legal basis for a new trial

still some basis for hope

selected on the basis of test scores

b

: an underlying condition or state of affairs

hired on a trial basis

He is on a first-name basis with his customers.

c

: a fixed pattern or system

meets with us on a regular basis [=regularly]

The department sends reports on a daily basis. [=every day]

4

: the basic principle

concepts that form the basis of the country's economic policies

5

mathematics : a set of linearly independent vectors (see vector entry 1 sense 1a) in a vector space such that any vector in the vector space can be expressed as a linear combination of them with appropriately chosen coefficients (see coefficient sense 1)

Synonyms of basis

• foundation
• cornerstone
• bedrock
• justification

Examples of basis in a Sentence

The company does not hire employees on the basis of their race, sex, age, or religion.

the sole basis for the rumor is someone's overactive imagination

Recent Examples on the Web

The change effective Thursday means that arms sales requests from Syria will now be considered on a case-by-case basis. — Arkansas Online, 1 Oct. 2026

At Condé, Perlis will step in to lead the company on an interim basis. — Alex Weprin, HollywoodReporter, 30 Sep. 2026

On a net basis, the debt service payments amounted to $76 million this year. — Justin Birnbaum, Sportico.com, 30 Sep. 2026

Iraq has also opened talks with Turkey on closing its military bases inside Iraq, including the Bashiqa-Zilkan camp near Mosul. — Jane Arraf, NPR, 30 Sep. 2026

Word History

Etymology

Latin — more at base entry 1

First Known Use

14th century, in the meaning defined at sense 1

Phrases Containing basis

• basis point
• on a day-to-day basis
• on a first-come, first-served basis
• on a first-name basis
• on a friendly basis
• on a nightly basis
• on a rotating basis
• on a trial basis
• on the basis of
• on what basis

Rhymes for basis

• glacis
• mesas
• stasis
• anabasis
• cholestasis
• haemostasis
• hemostasis
• hypostasis
• periphrasis
• atelectasis
• bronchiectasis
• homeostasis

Kids Definition

basis

noun

ba·​sis ˈbā-səs 

plural bases ˈbā-ˌsēz 

: something on which some other thing is based or established

Medical Definition

basis

noun

ba·​sis ˈbā-səs 

plural bases -ˌsēz 

1

: any of various anatomical parts that function as a foundation

2

: base sense 2b

Legal Definition

basis

noun

ba·​sis ˈbā-səs 

plural bases -ˌsēz 

1

: something (as a principle or reason) on which something else is established

the court could not imagine any conceivable basis for the statute

see also rational basis

2

: a basic principle or method

especially : the principle or method by which taxable income is calculated

Note: The Internal Revenue Code has set some limits on which method a taxpayer may use for figuring taxable income. For example, a corporation with gross receipts under $5,000,000 may be a cash-basis taxpayer.

— accrual basis

: a method of accounting in which income and expenses are recorded in the period when they are earned or incurred regardless of when the payment is received or made

called also accrual method

— cash basis

: a method of accounting in which income and expenses are recorded in the period when payment is received or made

called also cash method

3

: the value (as cost or fair market value) of an asset used in calculating capital gains or losses for income tax purposes

— adjusted basis

: the basis of an asset increased or decreased to reflect changes in value (as through improvement or depreciation)

— carryover basis \ ˈkar-​ē-​ˌō-​vər-​ \

: the basis of a donated or transferred asset that is equal to the basis of the asset when it was in the hands of the donor or transferor

Note: Carryover basis is generally applied to gifts and to transfers in trust.

— cost basis

: the basis of an asset equal to the amount paid for the asset plus other acquisition costs

— stepped-up basis \ ˈstept-​ˈəp-​ \

: the basis of inherited property equal to its market value at the decedent's date of death or to an alternate valuation

— substituted basis

: the basis of property received in exchange for property of a like kind that is equal to the basis of the property given with adjustments for additional consideration received or gains and losses realized