key
//kiː//
Noun
A small metal instrument specially cut to fit into a lock and move its bolt to open or close it.
I lost my house key.
A means of access, control, or understanding something.
Education is the key to success.
A button or lever on a keyboard, typewriter, or musical instrument that is pressed to produce a character or sound.
Press the Enter key to continue.
A system of musical tones based on their relationship to a tonic note.
This song is written in the key of C major.
A set of answers to a test or exercise.
The teacher provided an answer key for the homework.
A low-lying island or reef, especially in the Caribbean.
The Florida Keys are a chain of tropical islands.
Adjective
Of crucial importance; essential or fundamental.
Education is a key factor in reducing poverty.
Verb
To enter or input data using a keyboard.
She keyed in her password and logged into the system.
To scratch or damage a car's paintwork with a key.
Someone keyed my car in the parking lot.