Isolated Queen's Pawn (IQP)

An isolated queen's pawn (IQP) is a central pawn with no friendly pawns on the files beside it, so no pawn can ever defend it. The side that has it gets active, attacking pieces in the short term; the other side tries to blockade it and win it later. It's a classic trade of activity now versus a weakness later.

Source for further study: Baburin, Winning Pawn Structures.