pockets
2. A small patch of something.
‘some of the gardens still had pockets of dirty snow in them’
'When we took the family walk to the park we'd pass through pockets of warmth, as if someone had saved summer in a bottle and dropped it on the sidewalk for all to enjoy.’
2.1 A small, isolated group or area.
‘there were pockets of disaffection in parts of the country’
‘From rooftops to alleys, combined military forces are battling pockets of remaining fighters.’
‘The city is small and comforting, and its people live in genteel pockets of suburbia and have 1950s good manners.’
2.2 A cavity in a rock or stratum filled with ore or other material.
‘This suggests that the mantle convects as a whole, although the geochemists now require an explanation for the existence of pockets of unmixed mantle material.’
https://www.lexico.com/definition/pocket
