Gram (g)
Definition: A gram (symbol: g) is a metric unit of mass. It is defined as one thousandth of a kilogram, the base unit of mass in the International System of Units (SI).
History/origin: The gram was originally defined in 1795 as the absolute weight of a volume of pure water equal to the cube of the hundredth part of a meter, and at the temperature of melting ice. Today, it is defined in terms of the kilogram.
Current use: The gram is widely used in science, cooking, and commerce. It is a common unit for measuring the weight of small items, food ingredients, and precious metals.
Ounce (oz)
Definition: An ounce (symbol: oz) is a unit of mass in the imperial and US customary systems of measurement. It is defined as exactly 28.349523125 grams. There are 16 ounces in a pound.
History/origin: The ounce has been used as a unit of measurement since ancient Roman times. The word "ounce" comes from the Latin "uncia" (one-twelfth). The modern international avoirdupois ounce was defined in 1959 as exactly 28.349523125 grams.
Current use: The ounce is primarily used in the United States, United Kingdom, and Canada. It is commonly used for measuring food ingredients, postal items, and precious metals (troy ounce).