ectoderm vs neural tube

ectoderm and neural tube both are nouns.

Word	Noun	Adjective	Verb	Adverb
ectoderm	Yes	No	No	No
neural tube	Yes	No	No	No

As nouns, neural tube is a hyponym of ectoderm; that is, neural tube is a word with a more specific, narrower meaning than ectoderm:

ectoderm: the outer germ layer that develops into skin and nervous tissue
neural tube: a tube of ectodermal tissue in the embryo from which the brain and spinal cord develop

ectoderm (noun)	neural tube (noun)
the outer germ layer that develops into skin and nervous tissue	a tube of ectodermal tissue in the embryo from which the brain and spinal cord develop