Diameter

(di-ăm'e-tur.) [FromGr. diametreo, I measure through. (Geom.) A right line pa ing through the centre of a circle or other curvilinear figure, and terminated at each extremity by the circumference. It thus divides the circle into 2 equal parts, and is the greatest chord; hence we have a method of describing a semicircle upon any line, by a uming its middle point for the centre. The D. of a circle is to the circumference as 1 to 31416, or as 7 to 22 nearly. The square of the D. multiplied by 7854 is the area. The cube of the D. ofa sphere multiplied by 5236 gives the solid contents. [s. 283]