A daymark is a navigational aid for sailors and pilots, distinctively marked to maximize its visibility in daylight.[1]
The word is also used in a more specific, technical sense to refer to a signboard or daytime identifier that is attached to a day beacon or other aid to navigation.[2] In that sense, a daymark conveys to the mariner during daylight hours the same significance as the aid's light or reflector does at night.[3] Standard signboard shapes are square, triangular, and rectangular, while the standard colours are red, green, orange, yellow, and black.[2]