Segment
in comparative anatomy, one of the divisions or rings in the body of an insect, an annelid, a decapod, crustacean, etc. In geometry, a segment is a part cut off from any figure by a line or plane. The segment of a circle is a part of the area of a circle included between a chord and the arc which it subtends. An angle in a segment is the angle contained by any two straight lines drawn from any point in the arc and terminating in the extremities of the chord. Similar segments of circles are those which contain equal angles, or whose arcs contain the same number of degrees. A spherical segment is a portion of a sphere bounded by a secant line and a zone of the surface. If a circular segment be revolved about a radius drawn perpendicular to the chord of the segment, the volume generated is a spherical segment. SEGNO (sā'nyo), in music, a sign or mark used in notation in connection with repetition. Al segno (to the sign), a direction to return to the sign; dal segno (from the sign), a direction to repeat from the sign.