Omnibus account
The account one might find upstairs on the Clapham number 88.
“Omnibus”, as Latin scholars will tell you, means “all”. Just as the clapham omnibus was originally conceived as a mode of transport for all, so an omnibus account is a customer account for all: a single account where a custodian holds, and commingles, assets on behalf of a number of its clients.
Seeing as a custodian may not mix up its own “house” assets with those of its clients, so an omnibus is necessarily and exclusively a client account.
Compare and contrast with a nostro account, which by the same latinate token, is necessarily and exclusively, a bank’s own proprietary account.
Loose-lipped operations folk merrily confuse the two, which will drive your CF10A — and to a lesser extent those grammar pedants in legal — up the freaking wall.