Limit order
Also called: resting order
An order that names your own price instead of taking whatever the market is at right now.
In practice
A market order fills immediately at the current price. A limit order waits: you say what you'll pay, and it fills only if the market reaches it. Naming your own price is the difference between deciding and accepting.
What it is not
Not a guarantee. If the price never reaches your level the order simply doesn't fill — and even when it does touch briefly, an order can be missed. That is true of real limit orders too, not just ours.