1. To copulate so as to produce children or offspring with. The female praying mantis is notorious for eating the head of its male mate after—or sometimes while—mating with him. A: "She's a nice girl and all, but I don't know if she's someone I'd want to mate with." B: "Ugh, can you please not refer to it as mating?"

2. To pair an animal with a mate so that the two will copulate and produce offspring. In this usage, a noun or pronoun is used between "mate" and "with." I'm been mating my English bulldog with a number of female dogs around the state.