baby tooth vs deciduous tooth

baby tooth and deciduous tooth both are nouns.

Word	Noun	Adjective	Verb	Adverb
baby tooth	Yes	No	No	No
deciduous tooth	Yes	No	No	No

As nouns, baby tooth and deciduous tooth are synonyms defined as:

baby tooth and deciduous tooth: one of the first temporary teeth of a young mammal (one of 20 in children)

Other synonyms of baby tooth include milk tooth, primary tooth.

baby tooth (noun)	deciduous tooth (noun)
one of the first temporary teeth of a young mammal (one of 20 in children)	one of the first temporary teeth of a young mammal (one of 20 in children)