reply to Mr_Otis
said by Mr_Otis :No, they're not. There are single-shot firearms of various kinds; single-action revolvers; magazine-fed bolt-action, pump and lever action firearms, etc. Double-action revolvers could be thought of as "semi-automatic," in that they operate as you describe, but they're not regarded as such.
Aren't all guns 'semi-automatic'? At least, all those that are not machine guns? Pull the trigger, gun fires. Pull the trigger, gun fires. Semi-automatic.