Origin

This character combines a boat (舟) on the left with 玄 on the right. The 玄 component here functions as a sound hint—its pronunciation "gen" matches the on'yomi reading. The left side, the boat radical, establishes that this term relates to ships. Together, the combination points to a specific part of a ship: the gunwale, which is the upper edge or side rail of a boat's hull. The sound component 玄 helps speakers remember both the meaning and how to pronounce the word.