<p><strong>Noun:</strong></p><ul><li>a line bounding or marking off an area: The police created a perimeter with caution tape around the crime scene.</li><li>the outermost limits: Under the new regulations, the smoke-free area for playgrounds and sports areas extends 20 meters from the perimeter of each site.</li><li>Geometry: the border or outer boundary of a two-dimensional figure.</li><li>the length of such a boundary.</li><li>Military: a fortified boundary that protects a troop position.</li><li>Ophthalmology: an instrument for determining the peripheral field of vision.</li><li>Often the perimeter.</li><li>Basketball: Also called three-point line.</li><li>a semicircular line on a basketball court surrounding the basket, outside of which field goals are worth three points rather than two.</li><li>three-pointer (def).</li><li>the area outside this line (often used attributively): There's no player in the NBA who puts more pressure on opposing defenses from the perimeter than him.</li><li>The team needs an efficient point guard with a great perimeter shot.</li></ul>