Lewis & Short

rătĭōcĭnĭum, ii, n. [ratiocinor],

  1. I. a reckoning, computation, Col. 5, 1 fin.; 5, 2, 6; 5, 11, 13; Cod. Th. 8, 1, 6: publica, ib. 9, 16, 2.
  2. II. The obligation to render an account: imponere, Cod. 2, 7, 6 al.