bubble

bubble
 n.— «Technically, Scotto explains, donks are Caprices or Impalas from the years 1971 to 1976. (One theory about the provenance of the name “donk” is the resemblance of the Impala logo to a donkey; another is that it derives from a slang term for a shapely posterior.) A similarly customized Caprice or Impala from model years 1977 to 1990 is a box, and ‘91s through ‘96s are bubbles, names that reference the cars’ silhouettes. Scotto’s magazine uses the term hi-risers to cover the entire category, but most any tricked-out boxy ‘70s sedan is now routinely called a donk. The key is “really big wheels, wheels that obviously do not fit in the wheel well,” Scotto continues, adding that these days, you really need 24-inch wheels to qualify.» —“Donk My Ride” by Rob Walker New York Times June 17, 2007. (source: Double-Tongued Dictionary)