1. going down; fall; decrease; drop
2. knocking down (in boxing); flooring; being knocked down; being floored
3. being out of action (due to illness, exhaustion, etc.); being down (e.g. with a cold); being knocked out (from alcohol); being out of it; collapsing
4. going down (of a computer system, server, etc.); crashing
5. (number of) outs
6. being down (in points, games, etc.); behind behind; trailing
7. down (American football)
8. down (feathers)