sailor's breastplate vs prolonge knot

sailor's breastplate and prolonge knot both are nouns.

Word	Noun	Adjective	Verb	Adverb
sailor's breastplate	Yes	No	No	No
prolonge knot	Yes	No	No	No

As nouns, sailor's breastplate and prolonge knot are synonyms defined as:

sailor's breastplate and prolonge knot: a knot in the rope used to drag a gun carriage

sailor's breastplate (noun)	prolonge knot (noun)
a knot in the rope used to drag a gun carriage	a knot in the rope used to drag a gun carriage