Meaning of keyway

key•way

1. a groove in a shaft, the hub of a wheel, etc., for receiving part of a key holding it to another part.
2. a slot in a lock for receiving and guiding the key.
3. (in poured-concrete construction) a longitudinal groove in a footing, or in a pour that has set, providing a key for newly poured concrete.
4. a depression or slot carved into rock to provide a bond or anchorage for a structure, as a dam.