Synonyms for Pocket (same or very similar meaning)
WordNet sense 1 (an enclosed space):
pouch, sac, sack
WordNet sense 2 (a hollow concave shape made by removing something):
scoop
WordNet sense 3 (a local region of low pressure or descending air that causes a plane to lose height suddenly):
air pocket, air hole
WordNet sense 4 (take unlawfully):
bag
From the ODE community, based on WordNet
add/edit