Definition of vera causa in English:
 vera causa
nounPlural verae causae ˌvɛːrə ˈkaʊzə
historical (in Newtonian philosophy) the true cause of a natural phenomenon, by an agency whose existence is independently evidenced.
 Example sentencesExamples
-  An unconscious idea is neither a vera causa nor a fact ultimately to be verified.
 -  This element of Newton's first Rule we can call by its common name, the vera causa principle.
 -  Explanation meant first detecting a vera causa, identifying a theoretically competent cause.
 -  But the doctrine of the vera causa has nothing to do with elementary conceptions.
 -  They admit variation as a vera causa in one case, they arbitrarily reject it in another, without assigning any distinction in the two cases.
 
Origin
  
Latin, literally 'real cause'.