Another way of saying "slow down" or "stop." Usually used when someone is being hasty about something and a wiser person says "Hold your horses!" to make them stop and think. Encourages someone to have caution.
Based on the times when people used wagons or carriages, and when they needed to keep them under control they would need to literally hold the horses back from running.
"Hold your horses," said Joe, "you don't know when the movie even starts."
a request to wait
Whoa, hold your horses there, big guy. We're not leaving yet.
It means to get your excitement under control../ (see cool yer jets)
Hold your horses, you'll get your turn.
Wait up. Don't get started yet. From the days of horse and buggy; hold the horses so they don't run off before you're ready.
Hold your horses! The boss isn't here yet.
Stop what you're doing. Stop right where you are.
Hey! Hold your horses, big boy! Your plan is all fucked up!
Well you should. If you don't hold onto your horse while riding it, you'll fall off and end up like Christopher Reeves.
Long story short, hold your horses or else you'll end up like Christopher Reeves