键 (jiàn): key (on keyboard), button

On my laptop keyboard, the space key suddenly stopped working, and I couldn't type any spaces at all.

My piano teacher made me practice this key repeatedly until I could play it accurately without mistakes.

Press the enter key on the keyboard once, and you can send this message.

When I was playing the game at a critical moment, I accidentally pressed the wrong key, and as a result, the character fell off the cliff.