from The Century Dictionary.
- noun In an organ or pianoforte, a pin which passes through a key of the keyboard and on which the key plays as on a pivot or center, so that when the front of the key is depressed by the finger the part on the other side of the pin, called the key-tail, rises. In each key one such pin is inserted.
Sorry, no etymologies found.
To insert a _rim-lock_, measure the distance from the selvage to the key-pin, locate this as the center of the keyhole, and bore the hole.
_ward_, _spring_, etc., the key-pin, into or around which the key is inserted, the _strike_, the plate attached opposite the selvage,