interjection Meaning, Definition & Usage

  1. noun an abrupt emphatic exclamation expressing emotion
    ejaculation.
  2. noun the action of interjecting or interposing an action or remark that interrupts
    interpellation; interposition; interpolation.

WordNet

In`ter*jec"tion noun
Etymology
L. interjectio: cf. F. interjection. See Interject.
Definitions
  1. The act of interjecting or throwing between; also, that which is interjected.
    The interjection of laughing. Bacon.
  2. (Gram.) A word or form of speech thrown in to express emotion or feeling, as O! Alas! Ha ha! Begone! etc. Compare Exclamation.
    An interjection implies a meaning which it would require a whole grammatical sentence to expound, and it may be regarded as the rudiment of such a sentence. But it is a confusion of thought to rank it among the parts of speech. Earle.
    How now! interjections? Why, then, some be of laughing, as, ah, ha, he! Shak.

Webster 1913