v.1. To fit something into some enclosed space for storage or travel: I packed our sandwiches in the picnic basket.
2. To fit something into some limited space: Do you think you could pack in a few more pairs of socks in your bag? There was not much room in the trunk for the bags, but I was able to pack them in.
3. To stop doing something, as a job or habit; retire from doing something: He packed in his career as a railroad engineer when the trains were sold. She wasn't making any money through her work, so she decided to pack it in.
4. To attract a large number of people: The speaker's seminars have been packing in audiences all month. Good marketing will pack audiences in at the premiere.