vena diploica vs vena

vena diploica and vena both are nouns.

Word	Noun	Adjective	Verb	Adverb
vena diploica	Yes	No	No	No
vena	Yes	No	No	No

As nouns, vena is a hypernym of vena diploica; that is, vena is a word with a broader meaning than vena diploica:

vena diploica: one of the veins serving the spongy part of the cranial bones
vena: a blood vessel that carries blood from the capillaries toward the heart

Other hypernyms of vena diploica include vein, venous blood vessel.

vena diploica (noun)	vena (noun)
one of the veins serving the spongy part of the cranial bones	a blood vessel that carries blood from the capillaries toward the heart