The name Llyr is a boy's name of Welsh origin meaning "the sea". Llyr and is often added to lists like Baby Names That Mean Ocean and discussed in our forums with posts like "Names on NB that make you go WOW!".
From the experts:
Llyr is a name with a great meaning and a lovely sound, but that sound is going to be next to impossible to get non-Welsh speaking people to pronounce (google the double L sound in Welsh). If you are outside Wales, you may wish to consider the Irish alternative Lir, which has the same meaning and an easier sound.