What does keyway mean?
A keyway is a shaped slot made for a key. In everyday use, it refers to the opening in a lock where the key is inserted and guided as the locking mechanism operates. In engineering, a keyway is a groove in a shaft, hub, or related part that receives a key, helping transmit rotation or torque between connected components. The word combines “key” with “way,” suggesting a passage or route for a key. Although often overlooked, a keyway must be accurately shaped and aligned for the key to fit and function properly. The term is especially useful in locksmithing, machinery, vehicle maintenance, and technical description, where distinguishing the slot from the key itself or from related features such as a keyseat is important.
nounA narrow, shaped slot made to receive and guide a key, especially in a lock, machine, shaft, or similar component.
- The shaped slot in a lock that receives the key and allows it to operate the locking mechanism.
- In engineering, a slot or groove in a shaft, hub, or other component intended to receive a key and transmit rotation or torque.
"The technician aligned the shaft with the keyway before securing the coupling."
"The key slid smoothly into the keyway, but the lock would not turn."
"The machinist checked the keyway for burrs before fitting the gear onto the shaft."
The plural is used when referring to multiple key slots or openings.
"The technician inspected the keyways in both hubs."
A keyway is where a key meets the machine: a narrow passage that turns a simple piece of shaped metal into a precise mechanical link.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does keyway come from?
“Keyway” is an English compound formed from “key” and “way,” meaning a way or passage for a key. The compound has been used for the slot in a lock and, later, for mechanical slots associated with keys. Its development follows the long-established use of “key” for both locking devices and the tapered pieces inserted into machines to secure or transmit force.
Related word forms
How keyway is actually used
The term is common in locksmithing and mechanical engineering. In machinery, it is often used specifically for a longitudinal slot in a shaft or hub, while a broader sense covers any channel designed to receive a key.
Easily confused with keyway
A keyway is the slot that receives a key, whereas a keyseat more specifically names the machined recess in a shaft or hub that supports it.