open-end wrench vs tappet wrench

open-end wrench and tappet wrench both are nouns.

Word	Noun	Adjective	Verb	Adverb
open-end wrench	Yes	No	No	No
tappet wrench	Yes	No	No	No

As nouns, open-end wrench and tappet wrench are synonyms defined as:

open-end wrench and tappet wrench: a wrench having parallel jaws at fixed separation (often on both ends of the handle)

open-end wrench (noun)	tappet wrench (noun)
a wrench having parallel jaws at fixed separation (often on both ends of the handle)	a wrench having parallel jaws at fixed separation (often on both ends of the handle)