v.1. To hold or maintain someone or something inside of something else: I wish you wouldn't keep the onions in the same drawer as the bread.
2. To restrain someone or something within some place: It's raining very hard, so keep the cat in tonight. I couldn't keep in my laughter when I heard the joke.
3. To provide someone with some information needed to take part in a group activity: We met with them every week to keep them in on the job that we were doing.