open-top bus

open-top bus (plural open-top buses)

1. (vehicles, UK) A double-deck bus with an open, or partially open, top deck.
   • 1951 October, R. S. McNaught, “Lines of Approach”, in Railway Magazine, page 704:

     At last the first glimpse from a bridge of an open-top red bus, and a noticeable darkening of the atmosphere from the smoke of London: then the increasingly dingy stations with double-barrel names, set amid what has always been to me the outstanding feature of the "Premier Line" approach to London—the positively marvellous display of crazy chimney-pots on the grey inner suburban houses. As many as twenty, all of varying style, standing together like ranks of jagged teeth, and providing a Dickensian back-cloth which no other route can boast.

See open-topper

• open-topper