Unit Definition (Teaspoon [US])
The teaspoon is a unit of volume used in food recipes. The U.S. teaspoon is equal to 1/3 tablespoon or 1/48 cup; this is equivalent to 1/6 fluid ounce, about 0.30 cubic inches, or approximately 4.9 milliliters.

Unit Definition (Tablespoon [UK])
The tablespoon is a unit of volume used in food recipes. In Britain, traditional tablespoons varied somewhat in size, and various older references give sizes in the range from 1/2 to 5/8 Imperial fluid ounce (14.2-17.6 milliliters). The traditional British tablespoonful was often equal to 4 teaspoonfuls or 1/10 teacupful.