Stall means to stop or delay. If your car stalls, it comes to a stop. When you want a horse to stop, you put him in a stall, or small enclosure inside a barn.
The word stall implies stopping something that will start again — a horse will leave the stall eventually and start moving, a stalled car can be restarted. Remember that when you're thinking about stall in the sense of postpone or delay. You can stall your professor from giving an exam by talking about last night’s big game. Your little sister can stall going to bed by asking for one more story. If you want to delay an approaching army, you might steal their boots — they'll still come but the "stall tactic" will buy you time.