Question

what is the use of key?​

Answer 1

$\tt \underline \orange{uses = }$

• The definition of a key is a metal instrument used for opening and closing a lock or operating a mechanical device. An example of key is what people use to open their car doors and start the engine.

$\tt \underline \blue{importance = }$

• As an adjective, key can mean "Of crucial importance" (Oxford). For example: the key facts are the most important facts, or a key worker is an employee whose role is especially vital. In British English, key in this sense is every bit as common and well-understood as crucial would be