Audio Equipment Question: What is this Jack/Port called? Answered

My friend and I are the only two members on our school's "Tech Team". We handle the audio during events in the auditorium. Well, the audio equipment is pretty old, and not very well taken care of. We came back from summer vacation and only have 4 working mics. Uh-oh. We have a bunch of dead cords, dead mics, an audio snake (is there a "proper" name for this?) with more than half the ports dead, and missing cables. Long story short, we have the task of getting new equipment (yay!). But first I need to know what this plug is called :/ So help me out? Anyone know this thing's official name?