The teaspoon is a unit of volume in the US customary system and uses the symbol Tsp.
In the kitchen, the teaspoon is the smaller of the commonly used spoons served at the table and represents 1/6 US fluid ounce, 1/48 US cup or, expressed in SI / metric format; 4.92892159375 ml.
A teaspoon is generally considered a cooking measure but is also used in the administration of medicine when in solution form; 5 ml or multiples thereof is the standard amount of liquid medicine across the world.
The register ton is a unit of volume in the shipping world and uses the symbol GRT.
1 register ton is equal to 100 ft³ or 2.832 m³.
The register ton is used in shipping to measure the amount of cargo on a vessel. The phrase is often mistaken for a unit of mass or weight because of the term 'ton' but should not be confused.