drop earring vs pendant earring

drop earring and pendant earring both are nouns.

Word	Noun	Adjective	Verb	Adverb
drop earring	Yes	No	No	No
pendant earring	Yes	No	No	No

As nouns, drop earring and pendant earring are synonyms defined as:

Other synonyms of drop earring include eardrop.

drop earring (noun)	pendant earring (noun)
an earring with a pendant ornament	an earring with a pendant ornament