hilum vs hilus

hilum and hilus both are nouns.

Word	Noun	Adjective	Verb	Adverb
hilum	Yes	No	No	No
hilus	Yes	No	No	No

As nouns, hilum and hilus are synonyms defined as:

hilum and hilus: (anatomy) a depression or fissure where vessels or nerves or ducts enter a bodily organ

hilum (noun)	hilus (noun)
(anatomy) a depression or fissure where vessels or nerves or ducts enter a bodily organ	(anatomy) a depression or fissure where vessels or nerves or ducts enter a bodily organ
the scar on certain seeds marking its point of attachment to the funicle