DICT.TW Dictionary Taiwan

 Tan·gent, a.  Touching; touching at a single point; specifically Geom. meeting a curve or surface at a point and having at that point the same direction as the curve or surface; -- said of a straight line, curve, or surface; as, a line tangent to a curve; a curve tangent to a surface; tangent surfaces.
 Tangent plane Geom., a plane which touches a surface in a point or line.
 Tangent scale Gun., a kind of breech sight for a cannon.
 Tangent screw Mach., an endless screw; a worm.
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 tangent plane
      n : the plane that contains all the lines tangent to a specific
          point on a surface