fontanelle vs soft spot

fontanelle and soft spot both are nouns.

Word	Noun	Adjective	Verb	Adverb
fontanelle	Yes	No	No	No
soft spot	Yes	No	No	No

As nouns, fontanelle and soft spot are synonyms defined as:

fontanelle and soft spot: any membranous gap between the bones of the cranium in an infant or fetus

Other synonyms of fontanelle include fontanel.

fontanelle (noun)	soft spot (noun)
any membranous gap between the bones of the cranium in an infant or fetus	a place of especial vulnerability
	any membranous gap between the bones of the cranium in an infant or fetus
	a sentimental affection