What is the first of the two terms of a ratio; the first or third of the four terms of a proportion. In the ratio a:b, a is the antecedent, and b the consequent called?

antecedent — (Math.) The first of the two terms of a ratio; the first or third of the four terms of a proportion. In the ratio a:b, a is the antecedent, and b the consequent. (Webster's 1913.)