Standard Lemma guide

onto

adj · prep · 4 senses · updated from the 2026-07-25 local source snapshot

Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.

Sound

Pronunciation

Each Play button uses your device's default local English voice, or a natural local fallback. The selected voice name appears after playback. This is synthesized speech, not a source recording.

  • Received-Pronunciation: /ˈɒn.tuː/
  • Southern-England: Recorded audio is listed in the source snapshot.
  • Northern-US, cot-caught-merger: /ˈɑn.tu/
  • US: cot-caught Recorded audio is listed in the source snapshot.
  • /ˈɔn.tu/ Midland US, Southern US, without the cot–caught merger
  • Northern-Ireland, Scotland: /ˈɔn.tʉ/
  • Received-Pronunciation: /ˈɒn.tə/
  • Northern-US, cot-caught-merger: /ˈɑn.tə/
  • /ˈɔn.tə/ Midland US, Southern US, without the cot–caught merger
  • Northern-Ireland, Scotland: /ˈɔn.tə/
  • Received-Pronunciation: /ˈɒn.tʊ/
  • Northern-US, before-vowel, cot-caught-merger, unstressed: /ˈɑn.tʊ/
  • /ˈɔn.tʊ/ Midland US, Southern US, without the cot–caught merger
  • rhymes with (unstressed, before consonants) -ɒntə
  • CMU ARPABET: AA1 N T UW0 Digits mark lexical stress: 1 primary, 2 secondary, 0 unstressed.
  • CMU ARPABET 2: AO1 N T UW0 Digits mark lexical stress: 1 primary, 2 secondary, 0 unstressed.

1

adj

Meaning 1

Attaining each of the values in its codomain; having its image equal to its codomain.

Definition source: English Wiktionary via Wiktextract

Usage: not-comparable

Topics: mathematics, sciences

Examples

  • Considered as a function on the real numbers, the exponential function is not onto, as it never takes on values less than or equal to zero.

Meaning relationships

Synonyms: surjective

Antonyms: none provided

2

prep

Meaning 2

Arriving upon or on top of (speaking of a physical or metaphorical movement).

Definition source: English Wiktionary via Wiktextract

Examples

  • My cat just jumped onto the keyboard.
  • A new drug has just come onto the market.

Meaning relationships

Synonyms: none provided

Antonyms: off, off of

3

prep

Meaning 3

Aware of.

Definition source: English Wiktionary via Wiktextract

Usage: informal

Examples

  • The thought-police were onto my plans of world domination.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

4

prep

Meaning 4

Being an onto function with a codomain of (see below).

Definition source: English Wiktionary via Wiktextract

Topics: mathematics, sciences

Examples

  • The exponential function maps the set of real numbers onto the set of positive real numbers.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

History

Etymology

From on + to, after into. Compare Saterland Frisian antou (“up to”).

Across languages

Translations

34 source translations are retained for this English entry.

  • Arabic: عَلَى (ʕalā) — upon; on top of
  • Arabic: على (ʕala) — upon; on top of
  • Arabic: عـ (ʕa) — upon; on top of
  • Bulgarian: върху (vǎrhu) — upon; on top of
  • Bulgarian: на (na) — upon; on top of
  • Dutch: op — upon; on top of
  • Esperanto: sur — upon; on top of
  • Finnish: päälle — upon; on top of
  • French: sur — upon; on top of
  • German: auf — upon; on top of
  • Gothic: 𐌰𐌽𐌰 (ana) — upon; on top of
  • Ancient Greek: ἐπί (epí) — upon; on top of
  • Hebrew: על (al) — upon; on top of
  • Icelandic: ofan á — upon; on top of
  • Icelandic: á — upon; on top of
  • Ido: adsur — upon; on top of
  • Irish: ar — upon; on top of
  • Italian: su — upon; on top of
  • Northern Kurdish: ser — upon; on top of
  • Marathi: -च्या वर (-cyā var) — upon; on top of
  • Occitan: subre — upon; on top of
  • Occitan: sus — upon; on top of
  • Occitan: sobre — upon; on top of
  • Polish: na — upon; on top of
  • Portuguese: sobre — upon; on top of
  • Portuguese: no — upon; on top of
  • Portuguese: na — upon; on top of
  • Russian: на (na) — upon; on top of
  • Lower Sorbian: na — upon; on top of
  • Spanish: sobre — upon; on top of
  • Swedish: upp på — upon; on top of
  • Turkish: üstünde — upon; on top of
  • Turkish: üstüne — upon; on top of
  • Welsh: ar — upon; on top of