Source : Webster's Revised Unabridged Dictionary (1913)

Causal \Caus"al\, a. [L. causalis. See {Cause}.]
   Relating to a cause or causes; inplying or containing a cause
   or causes; expressing a cause; causative.

         Causal propositions are where two propositions are
         joined by causal words.                  --Watts.

Causal \Caus"al\, n.
   A causal word or form of speech.

         Anglo-Saxon drencan to drench, causal of Anglo-Saxon
         drincan to drink.                        --Skeat.

Source : WordNet®

causal
     adj : involving or constituting a cause; causing; "a causal
           relationship between scarcity and higher prices"