planitudo
plānĭtūdo, ĭnis, f. [planus],
- evenness, levelness: planitudo, ὁμαλία, Gloss. Philox.
plānitūdo, inis, f. (planus), die Ebene, Boëth. instit. arithm. 2, 25. p. 112, 23 Fr.; 2, 28. p. 118, 20 Fr. u.a.
plānĭtūdō, ĭnis, f. (planus), surface plane : Boet. Arithm. 2, 25.