a priori

/ˌɑː pɹiˈɔːɹi/

//ˌɑː pɹiˈɔːɹi// adj

"a-priori" is a 7-letter English headword indexed on PlainSpell.

The verdict

“a priori” is uncommon English (outside the top frequency list), classed as an adjective. The kind of spelling people second-guess.

Unranked
below top-frequency English
8
letters

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Self-evident, intuitively obvious.

Corpus desk

Index EN-a-priori · a priori · English

a priori · unranked · 0 variants · 0 confusables

  • FREQ-UNRANKED Unranked
  • LEN-LONG 8 letters
  • VOW-4 4 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-THIN "A" thin
  • PHOTO-UNK Peer pending

Read with this headword: Spelling guide for this pattern

Desk codes from Wiktionary headword shape, FrequencyWords rank tier, confusable-pair count, generated misspelling depth, letter-cohort book size, and photo-finish peer. Not a difficulty grade.

Key facts for a priori
PropertyValue
Headworda priori
LanguageEnglish
Part of speechAdjective
IPA/ˌɑː pɹiˈɔːɹi/
Letters8
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “a priori” in English

a priorisits beyond the 100,000 most-frequent English words, in the long tail of technical, archaic, or otherwise rare vocabulary where spelling doubt tends to strike hardest.

Beyond rank #100,000. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

a priori is uncommon English outside the top frequency list, classed as anadjective, transcribed /ˌɑː pɹiˈɔːɹi/. Rarity is why readers land here mid-draft. 4 senses are on record.

No misspelling variants are generated for a priori in our index, suggesting the orthography follows predictable English patterns. Our confusable-pair dataset has no match for it, which usually means its spelling is distinct enough that readers don't reach for a similar-looking word instead.

Etymologically, the entry records: First attested in 1610. Learned borrowing from Medieval Latin ā priōrī (“involving reasoning from cause to effect; from first principles”, literally “from the former”). The correct English form is a priori, spelled A- -P-R-I-O-R-I.

Definition

  1. 1
    Self-evident, intuitively obvious.
  2. 2
    Presumed without analysis.
  3. 3
    Based on hypothesis and theory rather than experiment or empirical evidence.
  4. 4
    Developed entirely from scratch, without deriving it from existing languages.

Recorded use

Wiktionary examples

These source excerpts show how a priori appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.

  1. In his opening argument, the student mentioned nothing beyond his a priori knowledge.
  2. While the great critics drew their authority from the breadth of their reading, New Criterion critics often base their authority on an a priori rejection of the contemporary.

Etymology

First attested in 1610. Learned borrowing from Medieval Latin ā priōrī (“involving reasoning from cause to effect; from first principles”, literally “from the former”).

Synonyms

Antonyms

This word in other languages

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "a priori"?
"a priori" is spelled A- -P-R-I-O-R-I. The IPA pronunciation is /ˌɑː pɹiˈɔːɹi/.
What does "a priori" mean?
As an adjective, "a priori" means: Self-evident, intuitively obvious.
How do you pronounce "a priori"?
The IPA (International Phonetic Alphabet) transcription for "a priori" is /ˌɑː pɹiˈɔːɹi/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "a priori"?
First attested in 1610. Learned borrowing from Medieval Latin ā priōrī (“involving reasoning from cause to effect; from first principles”, literally “from the former”). See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list