On Definition

ŏn, ôn
preposition
In a position above, but in contact with and supported by; upon.
Webster's New World
In contact with (any surface); covering or attached to.
Webster's New World
Used to indicate location at or along.
The pasture on the south side of the river; a house on the highway.
American Heritage
So as to be supported by.
Leaning on his elbow.
Webster's New World
Used to indicate proximity.
A town on the border.
American Heritage
adverb
In or into a situation or position of contacting, being supported by, or covering.
Put your shoes on.
Webster's New World
In or into a position of being attached to or covering something.
Put your clothes on.
American Heritage
In a direction to or toward.
He looked on.
Webster's New World
In advance; forward; ahead.
Move on.
Webster's New World
Along in time; later; after.
Thirty years on, nothing had changed.
Webster's New World
Antonyms:
adjective
In action or operation.
The TV is on.
Webster's New World
Engaged in a given function or activity, such as a vocal or dramatic role.
You're on in five minutes!
American Heritage
Near or nearer.
Webster's New World
Under or behaving as if under observation.
A minister is always on.
American Heritage
Performing or functioning at a high level of competence.
He was really on in last night's game.
Webster's New World
Antonyms:
abbreviation
Old Norse.
Webster's New World
Ontario.
Webster's New World
Abbreviation of Old Norse.
Wiktionary
suffix
A discrete, small unit, such as a subatomic particle.
Baryon.
American Heritage Medicine
A property of a physical system when quantized as a particle.
Phonon.
American Heritage Medicine
A sequence of nucleotides or region of DNA.
Codon.
American Heritage Medicine
Inert gas.
Radon.
American Heritage
A chemical compound that is not a ketone or a compound that contains oxygen in a carbonyl group.
Parathion.
American Heritage
noun
The fact or state of being on.
Webster's New World
The on side.
Webster's New World

Dated form of eon.

Wiktionary
affix
An inert gas.
Radon.
Webster's New World
A subatomic particle.
Neutron.
Webster's New World
A functional unit.
Operon.
Webster's New World
A unit of measure.
Photon.
Webster's New World
prefix
Prefix meaning on, at, toward, upon.
Wiktionary

Other Word Forms of On

Noun

Singular:
on
Plural:
a 1

Idioms, Phrasal Verbs Related to On

Origin of On

  • From Middle English on, from Old English on, an (“on, upon, onto, in, into"), from Proto-Germanic *ana (“on, at"), from Proto-Indo-European *ano-, *nō- (“on"). Cognate with North Frisian a (“on, in"), Dutch aan (“on, at, to"), Low German an (“on, at"), German an (“to, at, on"), Swedish Ã¥ (“on, at, in"), Faroese á (“on, onto, in, at"), Icelandic á (“on, in"), Gothic 𐌰𐌽𐌰 (ana), Ancient Greek ἀνά (ana, “up, upon"), Albanian në (“in"); and from the Old Norse combination upp á: Danish pÃ¥, Swedish pÃ¥, Norwegian pÃ¥, see upon.

    From Wiktionary

  • From Old Norse ón, án (“without"), from Proto-Germanic *Ä“nu, *Ä“no, *ino (“without"), from Proto-Indo-European *anew, *enew (“without"). Cognate with North Frisian on (“without"), Middle Dutch an, on (“without"), Middle Low German āne (“without"), German ohne (“without"), Gothic [script?] (inu, “without, except"), Ancient Greek ἄνευ (áneu, “without").

    From Wiktionary

  • From Middle English on-, from Old English on-, an-, from Proto-Germanic *an-, *ana- (“on-”), from Proto-Indo-European *ano-, *nō- (“on”). Cognate with Dutch aan-, German an-, Swedish an-.

    From Wiktionary

  • From (electr)on (influenced by Greek -on) (neuter of -os n. and adj. suff.) (and -on) (neuter of -ōn n. and adj. suff.)

    From American Heritage Dictionary of the English Language, 5th Edition

  • Middle English from Old English an, on an- in Indo-European roots

    From American Heritage Dictionary of the English Language, 5th Edition

  • New Latin from (arg)on

    From American Heritage Dictionary of the English Language, 5th Edition

  • Alteration of –one

    From American Heritage Dictionary of the English Language, 5th Edition