A dado (US and Canada), housing (UK) or trench (Europe) is a slot or trench cut into the surface of a piece of machinable material, usually wood. When viewed in cross-section, a dado has three sides. A dado is cut across, or perpendicular to, the grain and is thus differentiated from a groove which is cut with, or parallel to the grain. Dados are often used to affix shelves to cabinetry bodies. Similar to the dado, see rabbet (rebate).