Core terms
Limit order
An order to buy at or below, or sell at or above, a set price. It controls the price but may not fill.
A buy limit at $3.00 fills only at $3.00 or better. If the price never comes back to $3.00, nothing happens. A limit order priced away from the current market rests on the book and waits its turn in the queue; one priced through the market (a buy limit above the ask) fills immediately up to its limit.
Limit orders are the standard choice in premarket and after hours, and in any stock where the spread is wide.
What traders should verify
Decide whether you need the fill or the price. Resting limits can miss the move; aggressive limits behave like capped market orders.
Do not conflate
A limit order can fill partly. Price priority does not guarantee a fill when many orders sit at the same price; queue position matters.