semi-automatic adjective 2noun 2forms 1 adjective2 •Partially automatic. •Of a firearm that automatically ejects a shell and loads the next one, but requires the trigger to be squeezed for each shot; autoloading.The pro-gun majority in the House of Representatives moved Wednesday to compel the nation's capital to broaden the rights of its residents to buy and own firearms, including semi-automatic weapons. — 2008 noun2 •A semi-automatic firearm, especially such a pistol. •A semi-automatic transmission. formssemi-automatics
