WordWeb Online

1. Involving or of the nature of synthesis (combining separate elements to form a coherent whole) as opposed to analysis
   "limnology is essentially a synthetical science composed of elements...that extend well beyond the limits of biology";
   - synthetic
    
2. (logic) of a proposition whose truth value is determined by observation or facts
   "'all men are arrogant' is a synthetical proposition";
   - synthetic

See also: a posteriori, inductive, logical