Lewis & Short

subsignātĭo, ōnis, f. [subsigno], a subscription, signature.

  1. * I. Lit.: veteres subsignationis verbo pro subscriptione uti solebant, Dig. 50, 16, 39.
  2. * II. Trop., a firm promise, assurance: poenitentiae, Tert. Poen. 2 med.