Definition of "double"
double
/ˈdʌbl̩/
adjective
not comparable
noun
plural doubles
(music) Playing the same part on two instruments, alternately.
verb
third-person singular simple present doubles, present participle doubling, simple past and past participle doubled
(music, intransitive, usually followed by "on") To be capable of performing (upon an additional instrument).
(radio, informal, of a station) To transmit simultaneously on the same channel as another station, either unintentionally or deliberately, causing interference.