Meaning of PLUS in English
Dealers in government bonds normally give price quotes in 32nds. To quote a bid or offer in 64ths, they use pluses; a dealer who bids 4+ is bidding the handle plus 4/32 + 1/64, which equals the handle plus 9/64.
Campbell R. Harvey. Hypertextual finance English glossary. Английский словарь гипертекстовых финансов. 2012