A jug — sometimes called a "bucket" — is a large positive hold that the climber can wrap their entire hand around, often with all four fingers curled inside a deep pocket or over a generous lip. Jugs are by far the easiest holds to use: they offer secure grip with minimal finger strength, low pulley load, and forgiving body positions.
In a climbing gym, jugs typically mark the start, finish, or rest holds of a route. On overhanging walls they're where you shake out, get chalk, and read the next sequence. Beginner routes are often dense with jugs because they let the climber focus on footwork rather than fighting to hold on.
As grades increase, jugs become rarer and the climbing relies more on crimps, slopers, pinches, and pockets. The progression from jug-dominated routes (V0–V1, 5.5–5.8) to pinch-and-crimp dominated routes (V4+ / 6c+) is one of the clearest markers of climbing progress. Don't take jugs for granted — savour them when they appear.