subwoofer UK /ˈsʌbˌwʊf.ə/US /ˈsʌbˌwʊf.əɹ/ noun1 •A loudspeaker designed to produce low-frequency sound, especially subbass.Hip-hop took the language and made it graffiti—it was music video on a wall with a beatbox blowing its subwoofers next to it. — 2004 formssubwoofers