a posteriori

adj

"a-posteriori" is a 11-letter English headword indexed on PlainSpell.

The verdict

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

Unranked
below top-frequency English
12
letters

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Involving induction of theories from facts.

Corpus desk

Index EN-a-posteriori · a posteriori · English

a posteriori · unranked · 0 variants · 0 confusables

  • FREQ-UNRANKED Unranked
  • LEN-MEGA 12 letters
  • VOW-6 6 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 posteriori
PropertyValue
Headworda posteriori
LanguageEnglish
Part of speechAdjective
Letters12
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “a posteriori” in English

a posteriorifalls outside the top-100,000 ranked English words, the long-tail zone of technical, archaic, or low-frequency vocabulary, exactly where readers second-guess spellings most.

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

Rare enough to double-check

a posteriori is uncommon English outside the top frequency list, classed as anadjective. Rarity is why readers land here mid-draft. 2 senses are on record.

We couldn't generate a plausible misspelling set for a posteriori, which points to an orthography that plays by predictable English rules. No confusable counterpart is on file for this word, since nothing in our dataset looks or sounds close enough to cause mix-ups.

Etymologically, the entry records: Learned borrowing from Medieval Latin ā posteriōrī (“involving reasoning from effect to cause, from experience to theory”, literally “from what follows”). Popularized from the 19th century in reference to the work of Immanuel Kant. The correct English form is a posteriori, spelled A- -P-O-S-T-E-R-I-O-R-I.

Definition

  1. 1
    Involving induction of theories from facts.
  2. 2
    Of a constructed language, Developed on a basis of languages which already exist.

Recorded use

Wiktionary example

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

  1. What Locke calls "knowledge" they have called "a priori knowledge"; what he calls "opinion" or "belief" they have called "a posteriori" or "empirical knowledge".

Etymology

Learned borrowing from Medieval Latin ā posteriōrī (“involving reasoning from effect to cause, from experience to theory”, literally “from what follows”). Popularized from the 19th century in reference to the work of Immanuel Kant.

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 posteriori"?
"a posteriori" is spelled A- -P-O-S-T-E-R-I-O-R-I.
What does "a posteriori" mean?
As an adjective, "a posteriori" means: Involving induction of theories from facts.
What is the origin of the word "a posteriori"?
Learned borrowing from Medieval Latin ā posteriōrī (“involving reasoning from effect to cause, from experience to theory”, literally “from what follows”). Popularized from the 19th century in reference to the work of Immanuel Kant. 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