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lucid

American  
[loo-sid] / ˈlu sɪd /

adjective

  1. easily understood; completely intelligible or comprehensible.

    a lucid explanation.

    Synonyms:
    obvious, evident, understandable, plain
    Antonyms:
    obscure
  2. characterized by clear perception or understanding; rational or sane.

    a lucid moment in his madness.

    Synonyms:
    reasonable, sound
    Antonyms:
    irrational
  3. shining or bright.

    Synonyms:
    luminous, radiant
    Antonyms:
    dim
  4. clear; pellucid; transparent.

    Synonyms:
    limpid
    Antonyms:
    obscure

lucid British  
/ ˈluːsɪd /

adjective

  1. readily understood; clear

  2. shining or glowing

  3. psychiatry of or relating to a period of normality between periods of insane or irresponsible behaviour

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

Derived Forms

Etymology

Origin of lucid

First recorded in 1575–85; from Latin lūcidus, equivalent to lūc- (stem of lūx light 1 ) + -idus -id 4

Explanation

Something that's lucid is clear and understandable. Lucid writing is important in journalism, so that readers easily get the point of the article they're reading. When what you write or say is lucid, it's straightforward and its meaning is crystal clear. You can also use the adjective lucid to describe your mind or thoughts when you're thinking in a rational, sensible way: "I was worried about my grandmother's confusion yesterday, but she seems really lucid today." Another meaning is "translucent," or "letting light shine through" — which makes sense since lucid comes from the Latin lucidus, "light or clear," with its root of lux, "light."

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Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

"What we're seeing is a dose-response pattern where about 24 minutes of music with ABS seems to be the sweet spot," said Russo, Professor of Psychology at TMU and Chief Science Officer, LUCID.

From Science Daily • Mar. 16, 2026

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