The act of sending in or of putting in; insertion.
Specifically; (Zool.) The insertion of the male copulatory organ into the female in the process of coitus. "Four populations (of the vlei rat) varied in a number of parameters of copulatory behavior, such as latency to first mount, number of intromissions per series, and latency to intromission after first ejaculation."
The act of letting go in; admission.
(Scots Law) An intermeddling with the affairs of another, either on legal grounds or without authority.