1. To fit or crowd a large number of things or people into a small space
   "We managed to pack in 200 people for the concert"
    
2. [informal] Stop doing something, especially to quit a job or abandon an activity
   "After years of struggle, he decided to pack in his music career"
    
3. [informal] To eat a large amount of food quickly
   "He packed in a huge breakfast before the long hike"
    
4. (outdoor activities) to carry supplies and equipment into a remote area, often for camping or hiking
   "We packed in enough food for a week-long trek"

Derived forms: packing in, packed in, packs in