Quick answer
Lindsay is a boy/girl name.
Meaning and history
This name comes from the English and Scottish surname Lindsay, which was originally derived from the name of the eastern English region of Lindsey, itself derived from the Celtic root lindos "lake" (referring to the town of Lincoln ) and Old English ieg "island". As a given name it was typically masculine until the 1960s (in Britain) and 70s (in America) after which time it became popular for girls, probably due to its similarity to Linda and because of American actress Lindsay Wagner (1949-).
Notes and context
Usage: english