Rowan has two convergent origins. The Irish/Scottish surname comes from ruadhán, meaning "little red one" (referring to red hair). The English word "rowan" refers to the rowan tree (mountain ash), considered protective against witches in Celtic and Norse folklore.
Rowan is unisex but increasingly used for girls in the U.S. It entered the top 1000 for girls in 1999 and has been climbing. Today it sits in the U.S. top 200 for girls.
Rowan reduces to eight — the number of rooted protection.