Definitions

1. conjunction

used to indicate a contrast or a simultaneous action

“I studied for the exam while watching TV.”

2. preposition

used to indicate a period of time during which something happens or is done

“She worked while her husband was away.”

3. noun

a period of time during which something happens or is done

“I took a break for a while.”

4. adverb

used to indicate a period of time during which something happens or is done

“She smiled while thinking about her childhood.”