from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun The study of the principles of reasoning, especially of the structure of propositions as distinguished from their content and of method and validity in deductive reasoning.
  • noun A system of reasoning.
  • noun A mode of reasoning.
  • noun The formal, guiding principles of a discipline, school, or science.
  • noun Valid reasoning.
  • noun The relationship between elements and between an element and the whole in a set of objects, individuals, principles, or events.
  • noun The nonarithmetic operations performed by a computer, such as sorting, comparing, and matching, that involve yes-no decisions.
  • noun Computer circuitry.
  • noun Graphic representation of computer circuitry.

from The Century Dictionary.

  • noun The science of the distinction of true from false reasoning, with whatever is naturally treated in connection therewith. See the phrases below.
  • noun [Dialectic and organon are generally synonyms of logic, though they have been variously distinguished at different times.]
  • noun Reasoning, or power of reasoning; ratiocination; argumentation; used absolutely, reason; sound sense.
  • noun The science of the necessary rules of thought: also called scientific logic: opposed to natural logic .
  • noun The logical doctrine applicable to natural things: opposed to the logic of faith, which is applicable to supernatural things (a distinction used in discussions on the Trinity).
  • noun An anthropological science which treats of the rules of the natural use of the understanding.
  • noun The logic of objective thought, or thought as it exists in the external world.
  • noun The science which expounds the laws by which our scientific procedure should be governed, so far as these lie in the contents, materials, or objects about which our knowledge is conversant. Also called material logic.
  • Pertaining to God the Son as the Logos or Word of God.

from the GNU version of the Collaborative International Dictionary of English.

  • noun The science or art of exact reasoning, or of pure and formal thought, or of the laws according to which the processes of pure thinking should be conducted; the science of the formation and application of general notions; the science of generalization, judgment, classification, reasoning, and systematic arrangement; the science of correct reasoning.
  • noun A treatise on logic.
  • noun correct reasoning; ; also, sound judgment.
  • noun The path of reasoning used in any specific argument.
  • noun (Electronics, Computers) A function of an electrical circuit (called a gate) that mimics certain elementary binary logical operations on electrical signals, such as AND, OR, or NOT.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • adjective logical
  • noun uncountable A method of human thought that involves thinking in a linear, step-by-step manner about how a problem can be solved. Logic is the basis of many principles including the scientific method.
  • noun philosophy, logic The study of the principles and criteria of valid inference and demonstration.
  • noun uncountable (mathematics) The mathematical study of relationships between rigorously defined concepts and of proof of statements.
  • noun countable (mathematics) A formal or informal language together with a deductive system or a model-theoretic semantics.
  • noun uncountable Any system of thought, whether rigorous and productive or not, especially one associated with a particular person.
  • noun uncountable The part of a system (usually electronic) that performs the boolean logic operations, short for logic gates or logic circuit.
  • verb intransitive, pejorative To engage in excessive or inappropriate application of logic.
  • verb transitive To apply logical reasoning to.
  • verb transitive To overcome by logical argument.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun the principles that guide reasoning within a given field or situation
  • noun a system of reasoning
  • noun the branch of philosophy that analyzes inference
  • noun the system of operations performed by a computer that underlies the machine's representation of logical operations
  • noun reasoned and reasonable judgment


from The American Heritage® Dictionary of the English Language, 4th Edition

[Middle English, from Old French logique, from Latin logica, from Greek logikē (tekhnē), (art) of reasoning, logic, feminine of logikos, of reasoning, from logos, reason; see leg- in Indo-European roots.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Old French logike, from Latin logica, from Ancient Greek λογική (logike, "logic"), from properly feminine of λογικός (logikós, "of or pertaining to speech or reason or reasoning, rational, reasonable"), from λόγος (logos, "speech, reason").


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  • "Logic is little tweeting bird chirping in meadow. Logic is wreath of pretty flowers that smell bad." - Spock

    December 6, 2010

  • applied philosophy

    October 20, 2017