key

Definitions

A small piece of shaped metal used to operate a lock.

A crucial or essential element, person, or factor.

A set of musical notes based on a particular tonic note.

Examples

She fumbled in her bag to find the house key.

Hard work is the key to achieving your long-term goals.

Synonyms

essential crucial pivotal vital central fundamental critical

Antonyms

insignificant unimportant minor trivial peripheral secondary inessential