Something condensed has been made shorter, smaller, or thicker by removing extra parts — a condensed version of a book is a shorter one that keeps only the main story. In the kitchen, 'condensed milk' is milk with most of the water removed, so it becomes thick and sweet. In science, condensation is what happens when a gas cools and turns into a liquid, like water droplets forming on a cold glass — 'condensed' water is water that has changed from vapor into liquid this way.