To mantle or mantel in rock climbing is to perform a specific move, typically to get a climber up onto a ledge. The term is derived from the phrase mantel shelf and derives from the shelf above a fireplace. Imagine an old house with high cellings and an open fireplace with a shelf above it at chest height or slightly higher with a blank wall behind. The climber starts standing in the middle of the fireplace and ends standing on the mantel shelf and uses no hold except the mantel shelf. The motion is similar to that used in getting out of a swimming pool without using a ladder or steps
Reaching up, the climber puts one or both hands on the ledge and raises his body gradually. At some point the climber will be high enough to change the force being exerted, from pulling on the ledge, into pushing downwards with the hands (when the midpoint of the body is approximately at the level of the ledge). The climber then puts one foot on the ledge and transfers body weight to it before standing up without the use of holds on the wall behind the ledge. The move can be made without using any hold except the ledge itself though a foothold or smearing below the ledge will make the move easier. This move is usually performed when good handholds above the ledge either do not exist or are not reachable. The use of knees or other body parts is thought of as poor technique as it requires a subsequent, and often awkward, move to return the climber to the standing position.
The defining feature of the move is the presence of both feet and hands on the same hold at the same time. Thus any move where a foot and hand share the same hold for a brief period is sometimes referred to as a technical mantle, both because the move is harder (more technical) than a true mantle and because it is technically a mantle even though it doesn't look like a classic mantle.
There is some controversy as to whether the proper spelling of this term is mantle or mantel.