'modal logic' definitions:
Definition of 'modal logic'
From: WordNet
noun
The logical study of necessity and possibility
noun
A system of logic whose formal properties resemble certain moral and epistemological concepts
Definition of 'modal logic'
From: GCIDE
- modal logic \mo"dal log"ic\, n. A system of logic which studies how to combine propositions which include the concepts of necessity, possibility, and obligation. [PJC]