Pound (lbs)
Definition: The pound (symbol: lb) is a unit of mass used in the imperial and US customary systems of measurement. It is defined as exactly 0.45359237 kilograms. The pound is subdivided into 16 ounces.
History/origin: The pound has been used as a unit of weight since ancient times. The word "pound" comes from the Latin "libra" (scales). The modern pound was standardized in 1959 as exactly 0.45359237 kilograms.
Current use: The pound is primarily used in the United States, United Kingdom, and Canada. It is commonly used for measuring body weight, food products, and various other everyday items.
Kilogram (kg)
Definition: The kilogram (symbol: kg) is the base unit of mass in the International System of Units (SI). It is defined by taking the fixed numerical value of the Planck constant h to be 6.62607015×10⁻³⁴ when expressed in the unit J·s, which is equal to kg·m²·s⁻¹.
History/origin: The kilogram was originally defined in 1795 as the mass of one liter of water. In 1889, the International Prototype of the Kilogram (IPK) was created. In 2019, the kilogram was redefined in terms of fundamental physical constants.
Current use: The kilogram is used globally in science, engineering, and commerce. It is the standard unit of mass in most countries around the world.