[cf. old aged + SOUR lime] n. fermented lime juice, used as a condiment: 1978 Bahamian old sour:  two cups lime juice, one tablespoon salt. . .finely chopped [chili] pepper may be added. . As a seasoning Old Sour is used by many Bahamians. It keeps indefinitely, but can be used after it ferments, which occurs in about two weeks (Higgs 136). (Gen.)