A slat is a thin, flat strip of wood, metal, or plastic used in building furniture, fences, blinds, and other structures. Think of the horizontal pieces in window blinds that tilt to let light in or keep it out: those are slats. Park benches often have wooden slats that form the seat and backrest, with small gaps between them. Baby cribs use slats on the sides so parents can see in while keeping the baby safely contained.

Slats work together in parallel rows, each one separate but part of a larger structure. Venetian blinds might have dozens of thin slats strung together, all rotating at once when you pull a cord. A picket fence uses vertical slats to mark a boundary while still letting air and light pass through. Some beds have wooden slats under the mattress to provide support.

If something breaks into slats, or you can see between the slats, you're seeing these individual strips rather than one solid piece.