logic

¹

[loj-ik]

noun

1. the science that investigates the principles governing correct or reliable inference.

2. a particular method of reasoning or argumentation.

   We were unable to follow his logic.

3. the system or principles of reasoning applicable to any branch of knowledge or study.

4. reason or sound judgment, as in utterances or actions.

   There wasn't much logic in her move.

   Synonyms: cogency, sense

5. convincing forcefulness; inexorable truth or persuasiveness.

   the irresistible logic of the facts.

6. Computers.,  logic circuit.

-logic

²

1. a combining form used in the formation of adjectives corresponding to nouns ending in -logy:

   analogic.

logic

/ ˈlɒdʒɪk /

noun

1. 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 deduction induction

2. any particular formal system in which are defined axioms and rules of inference Compare formal system formal language

3. the system and principles of reasoning used in a specific field of study

4. a particular method of argument or reasoning

5. force or effectiveness in argument or dispute

6. reasoned thought or argument, as distinguished from irrationality

7. the relationship and interdependence of a series of events, facts, etc

8. to use excessively subtle or involved logic or argument

9. electronics computing

   1. the principles underlying the units in a computer system that perform arithmetical and logical operations See also logic circuit

   2. ( as modifier )

      a logic element

logic

1. 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.

logic

1. The branch of philosophy dealing with the principles of reasoning. Classical logic, as taught in ancient Greece and Rome, systematized rules for deduction. The modern scientific and philosophical logic of deduction has become closely allied to mathematics, especially in showing how the foundations of mathematics lie in logic.

Other Word Forms

• logicless adjective
• nonlogic noun

Word History and Origins

Origin of logic¹

First recorded in 1325–75; Middle English logik, from Latin logica, noun use of neuter plural (in Medieval Latin taken as feminine singular) of Greek logikós “of speech or reason”; logo-, -ic

Origin of logic²

< Greek -logikós. See logic

Word History and Origins

Origin of logic¹

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

Example Sentences

A June study from the University of Michigan suggests we are: even with blackout curtains, LED bulbs and thermostats locked at 72, our circadian rhythms still sway with the light, sleeping longer in winter and less in summer, echoing the old agricultural logic our bodies once obeyed.

From Salon

So the logic must surely be for option two: for new legislative elections.

From BBC

By this logic, since Americans are voluntarily taking the alleged drugs, does that make drug users material supporters of terrorism?

From Salon

Using this logic, I could almost write “JD Vance kills and eats babies,” and when — justifiably — challenged about it, I could insist it’s not a lie because he kisses babies with his mouth.

From Salon

If you follow Vance’s logic — which is, admittedly, hard to do because of his thicket of lies — this is what he’s saying: Democrats are withholding votes to pass a budget, which is forcing a government shutdown, and demanding that Republicans restore health care spending.

From Salon

Related Words

• philosophy 
• rationale 
• sanity 
• sense 

When To Use

What does -logic mean?

The combining form -logic is used like a suffix meaning “of or relating to a body of knowledge or writing.” In some rare instances, such as dialogic, -logic means "of or relating to a word or discourse," as in dialogic. It is occasionally used in scientific and technical terms.The form -logic comes from Greek -logikós, meaning “of speech or reason," which is derived from logos, meaning “word” or "discourse." To learn more about logos, you can read our entry on the English word logos here.What are variants of -logic?Though it doesn’t have any variants, the suffix -logic is related to the combining form -logy, which is used to form nouns related to adjectives that end in -logic, as in ecology. Additional related forms include -log and -logue. Want to know more? Read our Words That Use articles on all three forms.