Something that's divided is sectioned or split into parts. A divided political party might be separated into several groups with very different opinions on what the party's priorities ought to be.
Things can be physically divided, the way a pizza is when it's cut into eight separate pieces, or the way a highway is when it has a concrete barrier between lanes that go in different directions. There's also a figurative way of being divided, like a divided family that's feuding about something, or divided experts who disagree on the findings of a study. The adjective divided comes from the Latin dividere, "to force apart, cleave, or distribute."