Small embrasures for firing arrows or rifles.

Small openings in walls or stockades through which muskets were fired. Loopholes also served to permit light and air to enter a casemate or gallery.

In later castles, walls and towers were pierced at every level by loopholes or slits through which arrows or other missiles could be fired. The slits were often widened at the bottom in to a stirrup shape to broaden their fields of fire, and so that none was directly above another.

specific tax provisions that allow individuals or corporations to get out of part of their tax burden by engaging in actions favored by the government.