Found in the following dictionaries
OTCWL2014 (NASPA Word List 2014)
"Beatboxing" Definition
noun
The practice of using one’s mouth, lips, tongue, voice, etc. as a percussive instrument to create beats, rhythms and melodies for music, mainly hip hop.
Source: Wiktionary
verb
Present participle of beatbox.
Source: Wiktionary
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