A shaped device that opens or secures a lock.

A crucial element or decisive step toward a result.

A short guide to symbols or terms; an answer list.

A button on a keyboard or keypad.

A lever or valve on a musical instrument.

The tonality or scale of a musical composition.

A code or value used to grant access or encrypt data.

A small, low island of sand or coral.

To enter information by typing on a keyboard.

Essential; most important.