The word lock has several meanings:
- A mechanical fastening device which may be used on a door, vehicle, or container. Commonly, it can be released by using a key or combination. See locksmithing.
- Any means of holding a setting or state, such as caps lock, satellite lock.
- An enclosure in a canal used to raise or lower the water level for ships passing through: see canal lock.
- A wrestling hold, such as a head lock.
- A tuft or small bundle of hair.
- In computer science, a bookkeeping object associated with a piece of data used to serialize concurrent access. See lock (computer science).