Lb is the abbreviation for pound, a unit of weight used mainly in the United States. When you see “5 lb” on a bag of flour or a dumbbell, it means five pounds.

You'll see lb everywhere in American life: at the grocery store (“3 lb of apples”), in recipes (“add 1 lb of ground beef”), at the doctor's office (“you weigh 70 lb”), or at the gym (“can you lift 50 lb?”).

One pound equals 16 ounces, and for comparison, a stick of butter weighs about a quarter pound. Most other countries use kilograms instead of pounds. One kilogram equals about 2.2 pounds.

The plural can be written as “lb” or “lbs.” You might see either “5 lb” or “5 lbs” on packages, and both are acceptable.