in·ter·jec·tion / ˌintərˈjekshən/ • n. an abrupt remark, made esp. as an aside or interruption. ∎  an exclamation, esp. as a part of speech, e.g., ah! or dear me!DERIVATIVES: in·ter·jec·tion·al / -shənl/ adj.

INTERJECTION. A PART OF SPEECH and a term often used in dictionaries for marginal items functioning alone and not as conventional elements of sentence structure. They are sometimes emotive and situational: oops, expressing surprise, often at something mildly embarrassing, yuk/yuck, usually with a grimace and expressing disgust, ow, ouch, expressing pain, wow, expressing admiration and wonder, sometimes mixed with surprise. They sometimes use sounds outside the normal range of a language: for example, the sounds represented as ugh, whew, tut-tut/tsk-tsk. The spelling of ugh has produced a variant of the original, pronounced ‘ugg’. Such greetings as Hello, Hi, Goodbye and such exclamations as Cheers, Hurray, Well are also interjections.

interjection ejaculation XV; (gram.) XVI. — (O)F. — L. interjectiō, -ōn-, f. interject-, pp. stem of intericere interpose, f. INTER- + jacere throw.
So interject XVI.