n.
  - reasoning conducted or assessed according to strict principles of validity. ▸the quality of being justifiable by reason. ▸
(the logic of)
 the course of action following as a necessary consequence of. 
- a system or set of principles underlying the arrangements of elements in a computer or electronic device so as to perform a specified task.
Derivative
  
  Etymology
  ME: via OFr. logique and late L. logica from Gk logikē (tekhnē) ‘(art) of reason’.