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. The ounce is subdivided into 16 drams or 437.5 grains.
History/origin: The ounce has been used as a unit of weight since ancient Roman times. The word "ounce" comes from the Latin "uncia" (one-twelfth). The modern international avoirdupois ounce was standardized in 1959.
Current use: The ounce is primarily used in the United States and United Kingdom for measuring food portions, precious metals (troy ounce), and various other everyday items.
Gram (g)
Definition: The gram (symbol: g) is a unit of mass in the International System of Units (SI). It is defined as one one-thousandth of a kilogram, the SI base unit of mass.
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, at the temperature of melting ice.
Current use: The gram is used globally in science, medicine, and commerce. It is the most common unit of mass for small items like food ingredients, medications, and jewelry.