alligator wrench vs spanner

alligator wrench and spanner both are nouns.

Word	Noun	Adjective	Verb	Adverb
alligator wrench	Yes	No	No	No
spanner	Yes	No	No	No

As nouns, spanner is a hypernym of alligator wrench; that is, spanner is a word with a broader meaning than alligator wrench:

alligator wrench: a wrench with a v-shaped jaw and serrations on one side (resembles the open jaws of an alligator)
spanner: a hand tool that is used to hold or twist a nut or bolt

Other hypernyms of alligator wrench include wrench.

alligator wrench (noun)	spanner (noun)
a wrench with a v-shaped jaw and serrations on one side (resembles the open jaws of an alligator)	a hand tool that is used to hold or twist a nut or bolt