What does Merwyn mean?
Merwyn \m(e)-rw-yn\ as a boys' name. Merwyn's roots are Welsh, Old English and Old Welsh, and the name Merwyn means "sea friend; town by the lake". Merwyn is a variant of Marvin (Welsh): variant of Mervin. Merwyn is also a form of Merton (Old English): place name.
Merwyn is an uncommon given name for males. Merwyn is also a rare last name for both adults and children. (2000 U.S. Census)
Below is a charted analysis of the usage of the boy name Merwyn and related names. Marvin (#492 the previous year), Merton, Mervin and Mervyn are the popular alternative forms of Merwyn (#unlisted) rated in the Top 1000. Usage of these boy names was at its most widespread during 1920-1929 (usage of 0.485%) and is now significantly less (usage 0.127%, down 73.8%), with the forms Marvin, Merton and Mervin becoming less trendy. (2014 Birth Statistics)