資料來源 : Webster's Revised Unabridged Dictionary (1913)

   {Altitude of a pyramid} (Geom.), the perpendicular distance
      from the vertex to the plane of the base.

   {Axis of a pyramid} (Geom.), a straight line drawn from the
      vertex to the center of the base.

   {Earth pyramid}. (Geol.) See {Earth pillars}, under {Earth}.
      

   {Right pyramid} (Geom.) a pyramid whose axis is perpendicular
      to the base.