gastrointestinal tract vs alimentary canal

gastrointestinal tract and alimentary canal both are nouns.

Word	Noun	Adjective	Verb	Adverb
gastrointestinal tract	Yes	No	No	No
alimentary canal	Yes	No	No	No

As nouns, gastrointestinal tract and alimentary canal are synonyms defined as:

gastrointestinal tract and alimentary canal: tubular passage of mucous membrane and muscle extending about 8.3 meters from mouth to anus; functions in digestion and elimination

Other synonyms of gastrointestinal tract include alimentary tract, digestive tract, digestive tube, GI tract.

gastrointestinal tract (noun)	alimentary canal (noun)
tubular passage of mucous membrane and muscle extending about 8.3 meters from mouth to anus; functions in digestion and elimination	tubular passage of mucous membrane and muscle extending about 8.3 meters from mouth to anus; functions in digestion and elimination