half-moon vs lunule

half-moon and lunule both are nouns.

Word	Noun	Adjective	Verb	Adverb
half-moon	Yes	No	No	No
lunule	Yes	No	No	No

As nouns, half-moon and lunule are synonyms defined as:

half-moon and lunule: the crescent-shaped area at the base of the human fingernail

Other synonyms of half-moon include lunula.

half-moon (noun)	lunule (noun)
the crescent-shaped area at the base of the human fingernail	the crescent-shaped area at the base of the human fingernail
the time at which the Moon is at first or last quarter when half its face is illuminated