logic
Pronunciation: /ˈlɒdʒɪk/
noun
- 1reasoning conducted or assessed according to strict principles of validity: experience is a better guide to this than deductive logic the logic of the argument is faulty
- a particular system or codification of the principles of proof and inference: Aristotelian logic
- the systematic use of symbolic and mathematical techniques to determine the forms of valid deductive argument.
- the quality of being justifiable by reason: there seemed to be a lack of logic in his remarks
- (the logic of) the course of action suggested by or following as a necessary consequence of: the logic of private competition was to replace small firms by larger firms

Origin:
late Middle English: via Old French logique and late Latin logica from Greek logikē (tekhnē) '(art) of reason', from logos 'word, reason'