Lewis & Short

rectĭtūdo, ĭnis, f. [rectus] (post-class.).

  1. I. Straightness, directness. Lit., Aggen. ap. Front. p. 46 Goes.
  2. II. Trop., uprightness, rectitude (class. aequitas), Hier. in Isa. 8, 10; 26, 7: hominum, Just. Nov. 13 praef.