A pound is a unit of measuring mass. Your giant cat, at 16 pounds, may easily outweigh your tiny dog — and whether he does or not, he's definitely the boss.
Pound is one of those words with a dizzying number of meanings. There's the unit North Americans use to measure weight, and there's also the unit of currency in the U.K. that's basically equivalent to U.S. dollars. Egypt, Syria, and Lebanon, among other countries, also have pound currencies. As a verb, pound means "to hit or make a heavy thud," the way you pound a stake in the ground or your heart pounds when you're nervous.