Teaspoon

A teaspoon is a unit of volume. In the United States one teaspoon as a unit of culinary measure is $1/3$ tablespoon , that is, $\approx 4.93 mL$; it is exactly $1/6 U.S. fl. oz$, $1/48 \; cup$, and $1/768 \; U.S. liquid gallon$ (see United States customary units for relative volumes of these other measures) and approximately $1/3 cubic inch$. For nutritional labeling on food packages in the U.S., the teaspoon is defined as precisely $5 mL$.