log·ic (l?j??k) n. 1. The study of principles of reasoning, especially of the structure of propositions as distinguished from their content, and of method and validity in deductive reasoning. 2. a. A system of reasoning: Aristotle’s logic. b. A mode of reasoning: By that logic, we should sell the company tomorrow. c. The formal, guiding principles of a discipline, school, or science. 3. Valid reasoning: Your paper lacks the logic to prove your thesis. 4. The relationship between elements and between an element and the whole in a set of objects, individuals, principles, or events: There’s a certain logic to the motion of rush-hour traffic. 5. Computers a. The nonarithmetic operations performed by a computer, such as sorting, comparing, and matching, that involve yes-no decisions. b. Computer circuitry. c. Graphic representation of computer circuitry. [Middle English, from Old French logique, from Latin logica, from Greek logik? (tekhn?), (art) of reasoning, logic, feminine of logikos, of reasoning, from logos, reason; see leg- in the Appendix of Indo-European roots.] American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.logic (?l?d??k) n1. (Logic) the branch of philosophy concerned with analysing the patterns of reasoning by which a conclusion is properly drawn from a set of premises, without reference to meaning or context. See also formal logic, deduction4, induction42. (Logic) any particular formal system in which are defined axioms and rules of inference. Compare formal system, formal language3. the system and principles of reasoning used in a specific field of study4. a particular method of argument or reasoning5. force or effectiveness in argument or dispute6. reasoned thought or argument, as distinguished from irrationality7. the relationship and interdependence of a series of events, facts, etc8. (Logic) chop logic to use excessively subtle or involved logic or argument9. (Computer Science) electronics computing a. the principles underlying the units in a computer system that perform arithmetical and logical operations. See also logic circuitb. (as modifier): a logic element. [C14: from Old French logique from Medieval Latin logica (neuter plural, treated in Medieval Latin as feminine singular), from Greek logikos concerning speech or reasoning]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014log?ic (?l?d? ?k) n. 1. the science that investigates the principles governing correct or reliable inference. 2. symbolic logic. 3. a particular method of reasoning or argumentation. 4. the system or principles of reasoning applicable to any branch of knowledge or study. 5. reason or sound judgment, as in utterances or actions. 6. the consistency to be discerned in a work of art, system, etc. 7. any connection between facts that seems reasonable or inevitable. 8. a. the arrangement of circuitry in a computer. b. a circuit or circuits designed to perform functions defined in terms of mathematical logic. [1325?75; Middle English logik