Waterloo (n.)

Old English leah "open field, meadow, piece of untilled grassy ground," earlier læch, preserved in place names, from Proto-Germanic *lauhaz (source also of Old High German loh "clearing," and probably also Flemish -loo, which forms the second element in Waterloo), from PIE *louko- "light place" (source also of Sanskrit lokah "open space, free space, world," Latin lucus "grove, sacred grove, wood," Lithuanian laukas "open field, land"), from root *leuk- "to shine, be bright." The dative form is the source of many of the English surnames Lee, Leigh.