| Directrix 1. (n.) A directress. 2. (n.) A line along which a point in another line moves, or which in any way governs the motion of the point and determines the position of the curve generated by it; the line along which the generatrix moves in generating a surface. 3. (n.) A straight line so situated with respect to a conic section that the distance of any point of the curve from it has a constant ratio to the distance of the same point from the focus. Thesaurus Entries aeronautics, air lane, air route, air service, airway, astronautics, aviation, axis, ballooning, beeline, blind flying, chord, cloud-seeding, commercial aviation, contact flying, corridor, cruising, cut, cutoff, diagonal, diameter, direct line, directrix, edge, flight, flying, general aviation, gliding, great-circle course, lane, normal, path, perpendicular, pilotage, radius, radius vector, right line, sailing, sailplaning, secant, segment, shortcut, shortest way, side, soaring, straight, straight course, straight line, straight stretch, straightaway, streamline, tangent, transversal, vector, winging |