a priori

adjective

a pri·​o·​ri ˌä-prē-ˈȯr-ē 

ˌa-;

ˌā-(ˌ)prī-ˈȯr-ˌī 

-ˌprē-ˈȯr-ē

1

a

: deductive

b

: relating to or derived by reasoning from self-evident propositions compare a posteriori

c

: presupposed by experience

2

a

: being without examination or analysis : presumptive

b

: formed or conceived beforehand

a priori adverb

apriority

ˌä-prē-ˈȯr-ə-tē

ˌa-;

ˌā-(ˌ)prī-ˈȯr- 

-ˌprē-ˈȯr

noun

Did you know?

A priori and a posteriori are terms that are used especially in logic and philosophy. A priori is from Latin ā priōrī, which means literally, "from what is earlier." A priori knowledge is knowledge that comes from the power of reasoning based on self-evident truths; a priori usually describes lines of reasoning or arguments that proceed from the general to the particular, or from causes to effects. A posteriori is from Latin ā posteriōrī, which means literally, "from what is later." It describes knowledge based solely on experience or personal observation. So, for example, "Every apple is a fruit" is an a priori statement, since it shows simple logical reasoning and isn't a statement of fact about a specific case; "apples are sweet" is a posteriori, as it expresses something the speaker knows from experience.

Synonyms

• deducible
• deductive
• derivable
• inferable
• inferrible
• inferential
• reasoned

Examples of a priori in a Sentence

There's no a priori reason to think your expenses will remain the same in a new city.

an a priori argument for the defendant's innocence

Recent Examples on the Web

Knowing a priori which stocks will outperform the market is also much more difficult than reviewing the trends that occurred in the past. —Wayne Winegarden, Forbes, 2 Oct. 2024

Alongside this effort, wildlife trafficking should be designated as a predicate offense for wiretap authorizations, which would empower authorities to start gathering intelligence without having to prove a link to other crimes a priori. —Vanda Felbab-Brown, Foreign Affairs, 15 May 2023

Given Russia’s indiscriminate shelling and targeting, no type of conventional weapon should be excluded a priori. —Petr Fiala, Foreign Affairs, 24 Apr. 2023

And this abstractness of Mr. Wilson is part of a curiously a priori metaphysical idealism. —Dan McLaughlin, National Review, 6 Feb. 2024

Word History

Etymology

borrowed from Medieval Latin ā priōrī literally, "from what is earlier"

First Known Use

1652, in the meaning defined at sense 1a