1796, "having keys," from key (n.) in the musical sense. Also "to set the tone (of a musical instrument) to a particular key; hence figurative keyed up "excited, high-strung" (1889).
a keyed instrument
the locks have not yet been keyed
kewpie
kex
key
keyboard
keychain
keyed
keyhole
keyless
Keynesian
keynote
keypad
)window.location='https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=byronic106@yahoo.com&lc=US&item_name=Donation+to +Help+Keep+Etymonline+Free+and+Open&no_note=0&cn=&curency_code=USD&bn=PP-DonationsBF:btn_donateCC_LG.gif:NonHosted'){kind=link}