[from taste] n. 1. acidic citrus fruit, usually the lime (LITTLE SOUR) or Seville orange (BIG SOUR), but can include the lemon and grapefruit: 1895 Ol' man, come git some sour [limes] (Edwards 89). 1977 A sour—a lemon or lime (Albury 157). (Black)

2. [cf. SOUR 1] a condiment of citrus juice (usually lime or Seville orange) with salt and chopped hot peppers, often fermented: You could boil the jumbay and put sour (Acklins). = OLD SOUR, PEPPER SOUR (Black)