The acronym "lb." stands for pound, an imperial measurement of mass. Mass is a measure of how much matter is in a substance or object. The pound is equal to 16 ounces, which means that any amount of ounces can be converted to pounds by dividing them by 16.
Pounds are a standard imperial measurement unit, which is equivalent to the kilogram in the metric system. One pound is equal to 0.4536 kilograms. To convert a number of pounds to kilograms, multiply the pounds by 2.2046.
The acronym "lb." originally came from the Roman unit of measurement, "libra," which was equivalent to 12 Roman ounces.