» For other uses of the words gram or gramme, see gram (disambiguation). The gram (often gramme in British English), (Greek/Latin root grámma); symbol g, 's a unit of mass. Originally defined as "the absolute weight of a volume of pure water equal to the cube of the hundredth part of a metre, and at the temperature of melting ice" (later 4 °C), a gram's now defined as one one-thousandth of the SI base unit, the kilogram, or 1×10-3 kg, which itself's defined as being equal to the… (More on Gram)