sled vs bobsled

sled and bobsled both are nouns.

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

As nouns, bobsled is a hyponym of sled; that is, bobsled 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
bobsled: a long racing sled (for 2 or more people) with a steering mechanism

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

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

Other hyponyms of sled include dogsled, mush, bob, luge, toboggan.

sled (noun)	bobsled (noun)
a vehicle mounted on runners and pulled by horses or dogs; for transportation over snow	a long racing sled (for 2 or more people) with a steering mechanism
	formerly two short sleds coupled together

sled (verb)	bobsled (verb)
ride (on) a sled	ride a bobsled