1A man who is hired or paid by the day; a day labourer; specifically a colliery worker who is paid for the amount of time worked, rather than by the weight of coal produced. Compare daysman . Now chiefly historical.
2A man (especially a shift worker) who works during the day as opposed to at night.
A member of a ship's crew (as a carpenter, cook, sailmaker, etc.) who works only during the day, not being required to assist in keeping watch.
Late 16th century. From day + man.