gram	The base unit of mass in the Metric system.
liter	The base unit of volume in the Metric system.
meter	The base unit of length in the Metric system.
metric system	A widely used system of measurement that is based on the decimal system and multiples of 10.
prefix	A short set of letters that denote the size of measurement units in the Metric System. Metric prefixes include centi-, milli-, kilo-, and hecto-.
U.S. customary measurement system	The most common system of measurement used in the United States. It is based on English measurement systems of the 18th century.