Lewis & Short

causālis, e, adj. [causa] (rare and only late Lat.).

  1. I. Of or pertaining to a cause, causal: ratio, Aug. Gen. 7, 23.
    Subst.: Causālĭa, a work on the causes of things, Arn. 5, p. 163.
  2. II. In gram.: conjunctiones. which annex a reason for what precedes (e. g. nam, enim, itaque, etc.), Charis. p. 199 P.; Diom. p. 410 ib.; Prisc. p. 16, p. 1027 ib.
    Adv.: causālĭter, causally, Aug. l. l. 5 fin.; 6, 5.