The name Dag is a boy's name of Scandinavian origin meaning "daylight". Dag and is often added to lists like Names That Mean Hope and discussed in our forums with posts like "Names on NB that make you go WOW!".
From the experts:
Norse god who's the son of light plus historic diplomat Dag Hammarskjöld and author Dag Solstad combine to boost this Nordic name's appeal, but this could be difficult in English-speaking countries where the obvious tease will be "daggy Dag."