Lynn

At the time I was born the name Lynn was used about 50/50 male or female in Nebraska. My mom liked the name so much that whether I was a boy or a girl, that would be my name spelled Lynn if a boy (me) or Lynne if a girl. A boy across the street from me was also named Lynn, so although I always knew it could be a boy or girls name, I never felt any negative feeling about the name. About 10 years ago I first heard that Lynn was Welsh meaning waterfall. Then I also heard Lynn could mean a troll living under a waterfall who defrocked women.

The name Lynn also is short for Linda, which in Spanish is the word for "Beautiful".

Possibly a shortened form of Lyndsay.

Lynn may come from the Irish Gaelic name "Flynn," which means ruddy-complected.

I don't know about "linn" meaning "waterfall" in Scotland and Ireland, but it does indeed mean "pool"; hence Dublin's original Gaelic name "Dubh Linn" (DOOV linn), meaning "Black Pool". "Linn" also means "age" (as in a period of time) or "era" in Irish and Scots Gaelic.

Lynn is not just a Welsh term, but also Scottish and Irish. In Scottish placenames Linn can refer to a waterfall as well as a pool.