Lock
Definition: Used in the context of general equities. Make a market both ways (bid andoffer) either on the bid, offering, or an in-between price only. Locking on the offering occurs to attract a seller, since the trader is willing to pay (and ask) the offering side when others only ask it. Locking on the bid side attracts buyers for similar reasons. Typically, the sell side requires a plus tick to comply with short sale rules.