What is "manawydan"

Manawydan fab Llŷr is a figure of Welsh mythology, the son of Llŷr and the brother of Brân the Blessed and Brânwen. The first element in his name is cognate with the stem of the name of the Irish sea god Manannán mac Lir, and likely originated from the same Celtic deity as Manannán. Unlike Manannán, however, no surviving material connects him with the sea in any way except for his patronymic (llŷr is an old Welsh word for sea). Manawydan's most important appearances occur in the Second and Third Branches of the Mabinogi (the later of which is named for him), but he is also referenced frequently in medieval poetry and the Welsh Triads.