Meaning and name origin
Merwyn \m(e)-rw-yn\ as a boy's name is of Welsh, Old English and Old Welsh origin, and the meaning of Merwyn is "sea friend; town by the lake". Merwyn is a variant of Marvin (Welsh): variant of Mervin. Also a variant of Merton (Old English): place name.
Merwyn is not a popular first name for males and an equally uncommon surname or last name for all people (2000 U.S. Census).
Displayed below is a comparison of the popularity of the boy name Merwyn and its variant forms. Popular variation forms ranked in the Top 1000/100 are Marvin (#492), Mervin and Merton. (2014 statistics).