ETYM Latin interjectio: cf. French interjection. Related to Interject.
An action or remark that interrupts; SYN. interposition, interpolation.
In grammar, an exclamation; a word or phrase that can be used on its own to express emotion (surprise, anger, relief, and so on) or attract attention: “Phew! That was a near thing!”; “Oops! You’ve done it again!”; “Psst! Want to buy a cheap bike?” Interjections have no grammatical function and carry no meaning beyond their emotional charge.