Nounkey (on a piano, organ, etc.)

Nounblack key (on a piano, organ, etc.)

Noun, Suru verbkeystroke; typing · execution of test cases

Nounduplicate key · master key; passkey; skeleton key

Nounlocking doors; lock and key; vital point

Nounhidden mysteries; secret principle

Nouninternal lock

Nounwhite key (on a piano, organ, etc.)

Nountelegraph key (switching device used to send Morse code)

Nounmaster key; passkey; skeleton key

Nounrelay key

Nounpublic key

Nounprivate key (cryptography); secret key

Nounshared key

Nouncryptographic key; encryption key

Expressions (phrases, clauses, etc.), Nounkey success factor; key to success; KSF

Nounencryption key