1. to reduce the size of a garment.
> This is too big. I'll have to take it in around the waist.

2. to view and study something; to attend something involving viewing.
> The mountains are so beautiful! I need an hour or so to take it all in.
> I want to sit here a minute and take in the view.
> Would you like to take in a movie?

3. to receive money as payment or proceeds.
> How much did we take in today?
> The box office took nearly a thousand dollars in within just the last hour.

4. to receive something into the mind, usually visually.
> Could you take those explanations in? I couldn't.
> I could hardly take in everything she said.

5. to inhale, drink, or eat something.
> I think I'll go for a walk and take some fresh air in.