Pound
Definition: A pound (symbol: lb) is a unit of mass used in the Imperial and U.S. customary systems, defined as exactly 0.45359237 kilograms.
History/Origin: Originated from the Roman 'libra', a unit of weight, and was standardized through the British Imperial system in 1824 and later internationally in 1959.
Current Use: Used mainly in the United States, United Kingdom, and other countries that still use Imperial units for body weight, food, and goods.
Ounce
Definition: An ounce (symbol: oz) is a unit of mass equal to 1/16 of a pound or approximately 28.3495 grams.
History/Origin: Derived from the Roman 'uncia', meaning one-twelfth part, and standardized in the British Imperial system in the 19th century.
Current Use: Used in the United States and United Kingdom for measuring smaller weights like food portions, mail, and precious metals.