As a Noun: 1. A method of reasoning that involves a series of statements, each of which must be true if the statement before it is true. English = logic. As a Verb or Adjective: 1. Of conclusions, results or outcomes, to be the only one that can reasonably result from a particular set of facts or from a particular event. English = (be) logical. 2. To be true according to the rules of logic. English = (be) logical.