Definition - What does Keyway mean?
A Keyway is a slot that is cut in a shaft, wheel hub or in any pulley hub. A square key is placed in the keyway and mated with another similar keyway through which something can be hanged and lowered up and down. The keyway helps in ensuring that there is no relative rotation between two parts and it also enables torque transmission.
Petropedia explains Keyway
A keyway is joined with a key to form a system known as a keyed joint, which allows relative axial movement between two parts. The keyway also helps in preventing any slippage of hanging tools. At times, a keyway is also known as "key seat”. In drilling applications such as on a drilling rig, it is usually a slot cut on the edge of barge hull of a jackup drilling unit. This is the slot through which the drilling rig is mounted and through which drilling tools are lowered and removed from the well being drilled.