excircle

Noun

 * 1)  An escribed circle; a circle outside a polygon (especially a triangle, but also sometimes a quadrilateral) that is tangent to each of the lines on which the sides of the polygon lie.

Usage notes
Any given triangle has exactly three excircles. A quadrilateral that has an excircle is said to be (or sometimes ).

Translations

 * Finnish: viereen piirretty ympyrä, vierusympyrä
 * French: cercle exinscrit
 * Japanese:
 * Korean:
 * Portuguese: círculo exinscrito
 * Swedish: utvändig tangeringscirkel
 * Vietnamese: đường tròn bàng tiếp