Real Dictionary

disco
countable noun: A disco is a place or event at which people dance to pop music.

disco in American English
a nightclub or public place for dancing to recorded music played by a disc jockey
of discos, the music played there, etc.
to dance at a disco
adjective: of or pertaining to a disco or disco music
intransitive verb: to dance disco, esp. at a discotheque
noun: a discotheque

disco in British English
noun: an occasion at which typically young people dance to amplified pop records, usually compered by a disc jockey and featuring special lighting effects

disco- in American English
disk-shaped; discoid