or sem·i-au·to·mat·ic S0250800 (sĕm′ē-ô′tə-măt′ĭk, sĕm′ī-)adj.1. Partially automatic.2. Ejecting a shell and loading the next round of ammunition automatically, but requiring a squeeze of the trigger for each shot. Used of a firearm.n. A semiautomatic firearm.TranslationsThesaurusSeesemiautomatic