Webster's Revised Unabridged Dictionary · 1913

On

On (on) , preposition

[Old English on, an, o, a, Anglo-Saxon on, an; akin to Dutch aan, Old Saxon & German an, Old High German ana, Icelandic ā, Swedish å, Gothic ana, Russ. na, Latin an-, in anhelare to pant, Greek 'ana`, Zend ana. r195. Compare A-, 1, Ana-, Anon.]

The general signification of on is situation, motion, or condition with respect to contact or support beneath
1.
At, or in contact with, the surface or upper part of a thing, and supported by it; placed or lying in contact with the surface; as, the book lies on the table, which stands on the floor of a house on an island.
I stood on the bridge at midnight. — Longfellow
2.
To or against the surface of; -- used to indicate the motion of a thing as coming or falling to the surface of another; as, rain falls on the earth.
Whosoever shall fall on this stone shall be broken. — Matt. xxi. 44
3.
Denoting performance or action by contact with the surface, upper part, or outside of anything; hence, by means of; with; as, to play on a violin or piano. Hence, figuratively, to work on one's feelings; to make an impression on the mind.
4.
At or near; adjacent to; -- indicating situation, place, or position; as, on the one hand, on the other hand; the fleet is on the American coast.
5.
In addition to; besides; -- indicating multiplication or succession in a series; as, heaps on heaps; mischief on mischief; loss on loss; thought on thought. — Shakespeare
6.
Indicating dependence or reliance; with confidence in; as, to depend on a person for assistance; to rely on; hence, indicating the ground or support of anything; as, he will promise on certain conditions; to bet on a horse; based on certain assumptions.
7.
At or in the time of; during; as, on Sunday we abstain from labor. See At (synonym).
8.
At the time of; -- often conveying some notion of cause or motive; as, on public occasions, the officers appear in full dress or uniform; the shop is closed on Sundays.
in consequence of, or following; as, on the ratification of the treaty, the armies were disbanded; start on the count of three.
9.
Toward; for; -- indicating the object of some passion; as, have pity or compassion on him.
10.
At the peril of, or for the safety of.
Hence, on thy life. — Dryden
11.
By virtue of; with the pledge of; -- denoting a pledge or engagement, and put before the thing pledged; as, he affirmed or promised on his word, or on his honor.
12.
To the account of; -- denoting imprecation or invocation, or coming to, falling, or resting upon; as, on us be all the blame; a curse on him.
His blood be on us and on our children. — Matt. xxvii. 25
13.
In reference or relation to; as, on our part expect punctuality; a satire on society.
14.
Of. [Obsolete]
Be not jealous on me. — Shakespeare
Or have we eaten on the insane root That takes the reason prisoner? — Shakespeare

Instances of this usage are common in our older writers, and are sometimes now heard in illiterate speech.

15.
Occupied with; in the performance of; as, only three officers are on duty; on a journey; on the job; on an assignment; on a case; on the alert.
16.
In the service of; connected with; a member of; as, he is on a newspaper; on a committee.

On and upon are in general interchangeable. In some applications upon is more euphonious, and is therefore to be preferred; but in most cases on is preferable.

17.
In reference to; about; concerning; as, to think on it; to meditate on it.
They have added the -en plural form on to an elder plural. — Earle
We see the strength of the new movement in the new class of ecclesiastics whom it forced on to the stage. — J. R. Green
Collocations (8)
On a bowline (Nautical) , Same as Closehauled.
On a wind or On the wind (Nautical) , sailing closehauled.
On a sudden , See under Sudden.
On board or On draught or On fire , See under Board, Draught, Fire, etc.
On it or On't , of it. [Obsolete or Colloquial] — Shakespeare
On shore , on land; to the shore.
On the road or On the way or On the wing , etc. See under Road, Way, etc.
On to , upon; on; to; -- sometimes written as one word, onto, and usually called a colloquialism; but it may be regarded in analogy with into.

On , adverb

[See On, prep.]

1.
Forward, in progression; onward; -- usually with a verb of motion; as, move on; go on; the beat goes on.
Time glides on. — Macaulay
The path is smooth that leadeth on to danger. — Shakespeare
2.
Forward, in succession; as, from father to son, from the son to the grandson, and so on.
3.
In continuance; without interruption or ceasing; as, sleep on, take your ease; say on; sing on.
4.
Adhering; not off; as in the phrase, “He is neither on nor off,” that is, he is not steady, he is irresolute.
5.
Attached to the body, as clothing or ornament, or for use.
I have boots on. — B. Gonson
He put on righteousness as a breastplate. — Is. lix. 17
6.
In progress; proceeding; ongoing; as, a game is on.

On is sometimes used as an exclamation, or a command to move or proceed, some verb being understood; as, on, comrades; that is, go on, move on.

Collocations (1)
On and on , continuously; for a long time together. Toiling on and on and on. — Longfellow