Wordnet 3.0
VERB (1)
1. 
 crowd or pack to capacity; 
- Example: "the theater was jampacked"[syn: jam, jampack, ram, chock up, cram, wad]
WordNet (r) 3.0 (2006):
chock up
    v 1: crowd or pack to capacity; "the theater was jampacked"
         [syn: jam, jampack, ram, chock up, cram, wad]