An oarlock is a small metal fitting on the side of a rowing boat that holds an oar in place while you row. It is often a U-shape or a ring. The oar sits in it and can swing, but it should not jump out and float away. American English likes oarlock. British English more often says rowlock for the same piece — and though actually that word is written row-lock, people say it more like “roll-ock.” This “lock” is a holder, not a padlock on a door, but the idea is close: it keeps the oar where it belongs. You need two on a simple rowing boat, one for each oar. Racing shells may use a different kind of fitting, but the everyday word for the metal holder on a small boat is still this.

槳架（美式；英式常叫 rowlock）