Synonyms

What's the difference between Wmt-6c17f09eb2ea1f380eab8f9dc31b8e660fa4c9ce-sleigh (“sleigh”) and Wmt-51b2a2310a67a445b2c4544abb789c76adee2d91-sled (“sled”)? According to Wikipedia and various dictionaries they are synonyms.

OSM defines two different piste types for sleds: sleigh is for self-propelled sleds and sled for everything else. For more information see http://wiki.openstreetmap.org/wiki/Key:piste:type