From The Collaborative International Dictionary of English v.0.48 :
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.
[1913 Webster]
Causal propositions are where two propositions are
joined by causal words. --Watts.
[1913 Webster]
From The Collaborative International Dictionary of English v.0.48 :
Causal \Caus"al\, n.
A causal word or form of speech.
[1913 Webster]
Anglo-Saxon drencan to drench, causal of Anglo-Saxon
drincan to drink. --Skeat.
[1913 Webster]
From WordNet (r) 3.0 (2006) :
causal
adj 1: involving or constituting a cause; causing; "a causal
relationship between scarcity and higher prices"