adjective lu·cid \ˈlü-səd\

Definition of lucid

  1. 1 a :  suffused with light :  luminous b :  translucent <snorkeling in the lucid sea>

  2. 2 :  having full use of one's faculties :  sane

  3. 3 :  clear to the understanding :  intelligible





Examples of lucid in a sentence

  1. His lucid history of this grim subject is scrupulously accurate, so far as I am able to judge … —Richard A. Posner, New Republic, 8 Apr 2002

  2. “You would like me to read to you?” “You would oblige me greatly by doing so, Dorothea,” said Mr. Casaubon, with a shade more meekness than usual in his polite manner. “I am wakeful: my mind is remarkably lucid.” —George Eliot, Middlemarch, 1872

  3. The atmosphere, seen through a short space of half or three-quarters of a mile, was perfectly lucid, but at a greater distance all colours were blended into a most beautiful haze … —Charles Darwin, The Voyage of the Beagle, 1839

  4. The stroke also set off a major crisis of presidential succession, as the debilitated and not entirely lucid president continued to cling to office and plan feebly for re-election. —Beverly Gage New York Times Book Review, 13 Dec 2009

  5. He is able to recognize his wife in his lucid moments.

  6. <those lucid bands that spread across the arctic sky and are known as the northern lights>

Did You Know?

It's easy enough to shed some light on the origins of "lucid" - it derives, via the Latin adjective lucidus, meaning "shining," from the Latin verb lucēre, meaning "to shine." "Lucid" has been used by English speakers since at least the late 16th century. Although it once meant merely "filled with light" or "shining," it has developed extended senses describing someone whose mind is clear or something with a clear meaning. Other shining examples of "lucēre" descendants include "translucent," "lucent" ("glowing"), and the somewhat rarer "relucent" ("reflecting light" or "shining"). Even the word light itself derives from the same ancient word that led to "lucēre."

Origin and Etymology of lucid

Latin lucidus, from lucēre (see lucent)

First Known Use: 1591

Synonym Discussion of lucid

clear, transparent, translucent, limpid mean capable of being seen through. clear implies absence of cloudiness, haziness, or muddiness <clear water>. transparent implies being so clear that objects can be seen distinctly <a transparent sheet of film>. translucent implies the passage of light but not a clear view of what lies beyond <translucent frosted glass>. limpid suggests the soft clearness of pure water <her eyes were limpid pools of blue>.

clear, perspicuous, lucid mean quickly and easily understood. clear implies freedom from obscurity, ambiguity, or undue complexity <clear instructions>. perspicuous applies to a style that is simple and elegant as well as clear <a perspicuous style>. lucid suggests a clear logical coherence and evident order of arrangement <a lucid explanation>.

LUCID Defined for English Language Learners


adjective lu·cid \ˈlü-səd\

Definition of lucid for English Language Learners

  • : very clear and easy to understand

  • : able to think clearly

LUCID Defined for Kids


adjective lu·cid \ˈlü-səd\

Definition of lucid for Students

  1. 1 :  having or showing the ability to think clearly <lucid behavior>

  2. 2 :  easily understood <lucid writing>


adverb <The problem was lucidly explained.>

Medical Dictionary


adjective lu·cid \ˈlü-səd\

Medical Definition of lucid

  1. :  having, showing, or characterized by an ability to think clearly and rationally


noun plural


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