symposiast vs attender

symposiast and attender both are nouns.

Word	Noun	Adjective	Verb	Adverb
symposiast	Yes	No	No	No
attender	Yes	No	No	No

As nouns, attender is a hypernym of symposiast; that is, attender is a word with a broader meaning than symposiast:

Other hypernyms of symposiast include attendant, attendee, meeter.

symposiast (noun)	attender (noun)
someone who participates in a symposium	someone who waits on or tends to or attends to the needs of another
	a person who is present and participates in a meeting
	someone who listens attentively