All you ever didn't need to know about a door key:
-Parts of a key-
The head: This is relatively obvious, the handle-end of the key which you turn when the key is put into the lock.
The shaft: The elongated part of the key that meets with the pins inside of the lock and disappears when you insert the key into a lock cylinder.
The bow: This is more specifically the curvature of the wide section of the head of a key.
The nape: The part of the key between the head and the shaft that joins with the teeth.
The groove: The indented line(s) of the shaft that goes for the length of the teeth.
The teeth: The indentations on the keyshaft that meet with the pins inside of the lock after insertion of a key into a lock.