What is "on a sudden"

On \On\ ([o^]n), prep. [OE. on, an, o, a, AS. on, an; akin to D. aan, OS. & G. an, OHG. ana, Icel. [=a], Sw. [*a], Goth. ana, Russ. na, L. an-, in anhelare to pant, Gr. 'ana`, Zend ana. The general signification of on is situation, motion, or condition with respect to contact or support beneath; as:

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.
   --Shak.

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. Hence, 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. [Obs.] ``Be not jealous on me.''
    --Shak.

    Or have we eaten on the insane root That takes the reason prisoner?
    --Shak.

    Note: 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.

    Note: 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.

    On a bowline. (Naut.) Same as Closehauled.

    On a wind, or On the wind (Naut.), sailing closehauled.

    On a sudden. See under Sudden.

    On board, On draught, On fire, etc. See under Board, Draught, Fire, etc.

    On it, On't, of it. [Obs. or Colloq.]
    --Shak.

    On shore, on land; to the shore.

    On the road, On the way, 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.

    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.

Sudden \Sud"den\, n. An unexpected occurrence; a surprise.

All of a sudden, On a sudden, Of a sudden, sooner than was expected; without the usual preparation; suddenly.

How art thou lost! how on a sudden lost!
--Milton.

He withdrew his opposition all of a sudden.
--Thackeray.

adv. (context obsolete English) all of a sudden; suddenly