trade route vs seaway

trade route and seaway both are nouns.

Word	Noun	Adjective	Verb	Adverb
trade route	Yes	No	No	No
seaway	Yes	No	No	No

As nouns, trade route and seaway are synonyms defined as:

trade route and seaway: a lane at sea that is a regularly used route for vessels

Other synonyms of trade route include sea lane, ship route.

trade route (noun)	seaway (noun)
a lane at sea that is a regularly used route for vessels	a lane at sea that is a regularly used route for vessels
a route followed by traders (usually in caravans)