sled vs dog sled

sled and dog sled both are nouns.

Word	Noun	Adjective	Verb	Adverb
sled	Yes	No	Yes	No
dog sled	Yes	No	No	No

As nouns, dog sled is a hyponym of sled; that is, dog sled is a word with a more specific, narrower meaning than sled:

sled: a vehicle mounted on runners and pulled by horses or dogs; for transportation over snow
dog sled: a sled pulled by dogs

Other hyponyms of sled include bob, bobsled, bobsleigh, bobsled, bobsleigh, dog sleigh, dogsled, luge, pung, toboggan.

sled (noun)	dog sled (noun)
a vehicle mounted on runners and pulled by horses or dogs; for transportation over snow	a sled pulled by dogs

sled (verb)	dog sled (verb)
ride (on) a sled