The "head" is the top corner of a triangular sail, specifically where the luff (front edge) and leech (back edge) meet. It is the highest point of the sail, connected to a halyard to raise it. On square sails, this area features corner reinforcements called head cringles.

Key Details About the Head of a Sail:
Function: Serves as the attachment point for the halyard (line) used to hoist the sail up the mast or stay.

Location: The opposite end of the sail from the foot (bottom edge).

Components: In a triangular (Marconi) sail, it is a single corner point. In square sails, "head cringles" are grommets located at the top corners.

Distinction: Not to be confused with the "Head" (the bathroom/toilet on a boat).