
1) Brand of boat shoe 2) Shoe with a nonskid sole
Found on
https://www.crosswordclues.com/clue/topsider

Topsider (1974-1992) was an American Thoroughbred racehorse. He was a bay son of the great Northern Dancer and the very speedy racing mare Drumtop. Topsider won eight races from eighteen career starts, including the Sport Page Handicap at Aqueduct Racetrack in New York City. In another of his wins he set a new track record of 1:14 2/5 for 6½ furl...
Found on
http://en.wikipedia.org/wiki/Topsider

A topsider is a type of shoe, originally made from leather with a traction rubber sole and now made from canvas with a traction rubber sole, designed for use on board yachts.
Found on
http://www.probertencyclopaedia.com/browse/PT.HTM
No exact match found.