Lewis & Short

concĭnentĭa, ae, f. [concino] (postclass. for concentus),

  1. I. musical harmony, concord, Macr. Somn. Scip. 2, 2 fin.; 2, 3.
  2. II. Trop., in archit., symmetry: architectonica, Sid. Ep. 8, 4; Claud. Mam. Stat. Anim. 21.