1. a metal instrument used to open or close a lock
2. something that provides access, understanding, or a solution
3. a button on a keyboard, piano, or similar device

1. most important; essential

1. to enter data using a keyboard

Examples

• She lost her house key and couldn’t get inside.
• Education is the key to success.
• Press the Enter key to submit your answer.
• The song is written in the key of C major.
• Water is a key ingredient in this recipe.
• Please key in your password to log in.
• The detective found the key evidence at the crime scene.
• He keyed the data into the computer system.