means A small wave or series of small waves on the surface of water, or by extension any spreading effect that fans outward from a single point.

from English coined 'ripple' around the 17th century, and its deeper roots are genuinely murky — etymologists admit they aren't sure where it came from. It may be related to 'rip,' suggesting a tearing or roughening of a smooth surface, or it may simply be one of those imitative words that sound like the thing they name. Either way, the verb 'to ripple' came first; the little waves were named for what they do.