spelling bee vs spelldown

spelling bee and spelldown both are nouns.

Word	Noun	Adjective	Verb	Adverb
spelling bee	Yes	No	No	No
spelldown	Yes	No	No	No

As nouns, spelling bee and spelldown are synonyms defined as:

spelling bee and spelldown: a contest in which you are eliminated if you fail to spell a word correctly

Other synonyms of spelling bee include spelling contest.

spelling bee (noun)	spelldown (noun)
a contest in which you are eliminated if you fail to spell a word correctly	a contest in which you are eliminated if you fail to spell a word correctly