See also: toisa English Noun TOISA (plural TOISAs) (UK, finance, historical) Acronym of TESSA-only ISA, a form of cash ISA that could be opened using either capital that was originally invested in a TESSA and had not been withdrawn, or with funds transferred from another TOISA. Anagrams Ostia, ostia, Saito, Toias, stoai, IOTAs, taosi, Oatis, iotas, staioWikiwand - on Seamless Wikipedia browsing. On steroids.Remove ads