Other forms: dozens
A dozen is twelve. If you buy a dozen doughnuts for six people, everyone will get to eat two of them.
When you buy a dozen of something, you'll end up with twelve items. Your cat might, amazingly, have a dozen kittens, leading you to make a dozen phone calls trying to find homes for them all. Sometimes people use the word dozens to generically mean "a whole lot," as when you gasp, "There are dozens of seagulls sitting on my car!" Dozen has a Latin root, duodecim, "twelve."