A slate is a smooth, dark gray rock that splits naturally into thin, flat layers. For centuries, builders have used slate tiles to make waterproof roofs that last for generations. Students once wrote on small slate boards with chalk because paper was expensive, and they could simply wipe the slate clean to start fresh.

In politics and organizations, a slate means a list of candidates running together as a group. When a club elects officers, they might vote on a slate of candidates who have agreed to work together. Political parties often present a slate of candidates for different positions in an election.

The phrase clean slate comes from those old writing boards. When you start with a clean slate, you begin fresh without any mistakes or problems from the past. A teacher might give students a clean slate at the start of a new grading period, or friends might decide to wipe the slate clean after an argument and start over.

To slate something means to schedule it or designate it for a particular purpose. A movie might be slated for release next summer, or a building might be slated for demolition. The word suggests a firm plan, like writing it down on an old slate board.