Ok, the way I see it, rave can be both, 'rave' musical style and a 'rave' party ...
I can see lots of ppl not agreeing with me on this one, but as far as I'm informed, the musical style 'rave' dates back to early 90s, it is not played anymore since it has mostly split up in Jungle & Happy Hardcore ... if you want to hear what I mean, look for the album 'La Monza' by Raver's Nature ... check out "Monkey" or "The Music Turns Me On" ... the piano riffs and the happy synth loops are where happycore gets its roots, and the percussive breakbeat parts are the origins of Jungle.
"Rave" as a party is an underground party defined by electronic music, ie tekkno, trance, jungle, house ... whatever ...
Although because of this, 'rave' music has lost its original meaning and the term is used to describe electronic music in general, mostly the styles played at raves.
And one more thing, every rave (as in 'party') plays electronic muk, but not every party that plays electronic muk is a rave. For example, Innercity, Mayday, Love Parade etc. should not be considered raves, IMO ...

peace