in theory it is the minimum number of shares being offered @ that price, on this market its one of the cloak and dagger things i hate, in a world of standard board lots, we get 5000 share trades worth barely 50$
but what we really dont get to know is if theres millions of shares, or any at all behind those asks.
sometimes the only way to find out is hit the ask hard with volume , then see the MM all move up cause they were fulla the chit,