Typical milk consists of fat globules suspended in a nutrient solution. These globules of butterfat will separate easily from the milk - they float to the top of the solution, as what we commonly call cream. The left over liquid is skim milk.
With homogenized mlik, one shoots the milk through a really fine nozzle to break up the fat globules. As a result, the butterfat does not rise to the top and the milk is creamier - this process is called homogenization.
Person 1: Dude, what's up with this milk? It tastes really creamy!
Person 2: Well, my good friend, that's because the milk has been homogenized - it's homogenized milk! The cream that is normally taken out of milk to create skim milk is mixed back in, resulting in this tastey treat!
Person 1: Oh, I see! It tastes so good!