grapnel vs grapnel anchor

grapnel and grapnel anchor both are nouns.

Word	Noun	Adjective	Verb	Adverb
grapnel	Yes	No	No	No
grapnel anchor	Yes	No	No	No

As nouns, grapnel and grapnel anchor are synonyms defined as:

grapnel (noun)	grapnel anchor (noun)
a light anchor for small boats	a light anchor for small boats
a tool consisting of several hooks for grasping and holding; often thrown with a rope