The socket on a clubhead into which the shaft is fitted — the junction of shaft and head. The Equipment Rules keep it honest: the neck and socket may measure no more than 5 inches (127 mm) from top to sole, and only putters are free to attach the shaft anywhere on the head rather than at the heel. Modern adjustable drivers hide a sleeve adapter inside the hosel, which is how loft and lie change with a wrench turn. It also lends its name to golf's most dreaded miss: catch the ball on the hosel instead of the face and you've hit a shank.