From Longman Dictionary of Contemporary Englishdrum kitˈdrum kit noun [countable] 
APMa set of drums, used especially by professional musicians
APMa set of drums, used especially by professional musiciansExamples from the Corpus
drum kit• A multi-million pound industry in its own right, it cost 3 guitars and a drum kit to commence business.• Recently, Shields' college buddy Dave Harrison stepped in behind the drum kit to complete the lineup.• At the song's end, he casually tosses his guitar over his shoulder and into the drum kit. 