by definition

prep_phrase

"by-definition" is a 12-letter English headword indexed on PlainSpell.

The verdict

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

Unranked
below top-frequency English
13
letters

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - According to, or as a matter of, definition.

Corpus desk

Index EN-by-definition · by definition · English

by definition · unranked · 0 variants · 0 confusables

  • FREQ-UNRANKED Unranked
  • LEN-MEGA 13 letters
  • VOW-6 6 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-THIN "B" 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 by definition
PropertyValue
Headwordby definition
LanguageEnglish
Part of speechPrep_phrase
Letters13
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “by definition” in English

by definitionfalls 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

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

No misspelling variants are generated for by definition in our index, a straightforward case of a spelling with little room for common typos. This headword has no recorded confusable partner, which typically means the spelling is too distinctive to be mistaken for another word.

No explicit etymology string is stored for this entry, leaving phoneme-to-grapheme mapping as the best guide to its spelling rather than a borrowing history. The correct English form is by definition, spelled B-Y- -D-E-F-I-N-I-T-I-O-N.

Definition

  1. 1
    According to, or as a matter of, definition.
  2. 2
    Necessarily; always; certainly.

Recorded use

Wiktionary examples

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

  1. This property holds for all polygons; and since, by definition, all triangles are polygons, it holds for all triangles.
  2. Almost by definition, a conversation requires both parties to accept each other's viewpoints to some extent.

Synonyms

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 "by definition"?
"by definition" is spelled B-Y- -D-E-F-I-N-I-T-I-O-N.
What does "by definition" mean?
As a prep_phrase, "by definition" means: According to, or as a matter of, definition.
What language does "by definition" come from?
"by definition" is a English word. PlainSpell's reference spans five languages -- English, Spanish, Portuguese, French, and German -- with definitions, pronunciations, and spelling data for each.
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