noun log·ic \ ˈlä-jik \
|Updated on: 16 Aug 2018

Definition of logic

1 a (1) : a science that deals with the principles and criteria of validity of inference and demonstration : the science of the formal principles of reasoning
  • a professor of logic
(2) : a branch or variety of logic
  • modal logic
  • Boolean logic
(3) : a branch of semiotics; especially : syntactics
(4) : the formal principles of a branch of knowledge
  • the logic of grammar
b (1) : a particular mode of reasoning viewed as valid or faulty
  • She spent a long time explaining the situation, but he failed to see her logic.
(2) : relevance, propriety
  • could not understand the logic of such an action
c : interrelation or sequence of facts or events when seen as inevitable or predictable
  • By the logic of events, anarchy leads to dictatorship.
d : the arrangement of circuit elements (as in a computer) needed for computation; also : the circuits themselves
2 : something that forces a decision apart from or in opposition to reason
  • the logic of war


play \lō-ˈji-shən\ noun

Examples of logic in a Sentence

  1. If you just use a little logic, you'll see I'm right.

  2. There's no logic in your reasoning.

  3. There's some logic to what he says.

  4. There's a certain logic in what he says.

  5. The revolution proceeded according to its own logic.

  6. the logic of the situation

Recent Examples of logic from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'logic.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

How are logistics and logic related?

Logistics follows the same pattern of other plural nouns—such as ballistics, linguistics, statistics, or physics—that represent fields of study and take either a singular or plural verb.

Logic, used strictly in the singular, is a science that deals with the formal principles of reason. If a visitor walks in the house with wet hair, it is logical for one to assume that it is raining outside. Logistics, which involves such concerns as the delivery of personnel or supplies in an efficient manner, can often employ logic, such as by reasoning out the path least likely to interrupt the flow of a delivery:

As with many other areas of the economy, the digital revolution is having a profound effect on delivery logistics. The combination of mobile computing, analytics, and cloud services, all of which are fueled by the Internet of Things (IoT), is changing how delivery and fulfillment companies are conducting their operations.
—Andrew Meola, Business Insider, 14 Oct. 2016

Both logic and logistics ultimately derive from the Greek logos, meaning "reason." But while logic derives directly from Greek, logistics took a longer route, first passing into French as logistique, meaning "art of calculating," and then into English from there.

Origin and Etymology of logic

Middle English logik, from Anglo-French, from Latin logica, from Greek logikē, from feminine of logikos of reason, from logos reason — more at legend

LOGIC Defined for English Language Learners


Definition of logic for English Language Learners

  • : a proper or reasonable way of thinking about or understanding something

  • : a particular way of thinking about something

  • : the science that studies the formal processes used in thinking and reasoning

LOGIC Defined for Kids


noun log·ic \ ˈlä-jik \

Definition of logic for Students

1 : a proper or reasonable way of thinking about something : sound reasoning
  • There's no logic in what you said.
2 : a science that deals with the rules and processes used in sound thinking and reasoning

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