Green’s Dictionary of Slang

1. a large, portable cassette/CD/radio player.

1981		N.Y. Times 5 June D5/4: The portable stereo craze actually started three or four years ago with the so-called boom boxes - those blaring behemoths that can weigh up to 30 pounds and announce their presence a block away.
1990		S. Morgan Homeboy 17: Rap music hectored from the boombox on his shoulder.
1992		J. Mowry Way Past Cool 225: We just tryin to save for scorin usselfs a CD boomer.
2002		‘Touré’ Portable Promised Land (ms.) 199: You heard it flowing from boomboxes and lips, MTV and mix tapes.
2006		G. Iles Turning Angel 130: She takes her CD out of the boom box.
2013		T. Black ‘Eat Shit’ in Killing Time in Las Vegas [ebook] Turn that fucking music down you crazy fucking bitch! [...] or I’ll come over there and wrap that fucking boom-box round your scrawny motherfucking neck!
2016		A. Wheatle Crongton Knights 9: His dirty plate was on the bedside cabinet beside his boom box — some phone-in show was broadcasting.
2019		N. Walker Cherry 133: [T]he first sergeant hit the play button on the boom box and the Toby Keith song started playing.

2. in attrib. use of sense 1.

2007

D.S. Mitchell Killer Tune (2008) 31: The boom-box accoustics of the room caught his cry.