A bunker positioned immediately around the green rather than out in the fairway, built to catch and penalize missed approaches close to the hole. Unlike a fairway bunker shot, where the goal is distance, a greenside bunker shot is almost always an explosion shot: the club enters the sand an inch or two behind the ball and splashes sand and ball out together, rather than making clean contact. Rule 12.2 governs bunker play generally, but greenside bunkers carry the higher-stakes version of it — a player can't ground the club or touch the sand to test it before the stroke, under penalty of two strokes in stroke play. Many are also built shallow enough on the front lip that a golfer can still see the flag, a design courtesy dating to golf's earliest architects.
Source: https://golf.com/instruction/bunker-shots/difference-fairway-greenside-bunker-shots/, https://www.usga.org/content/usga/home-page/rules-hub/topics/bunkers.html · high confidence