lucid

adjective

lu·​cid ˈlü-səd 

1

a

: suffused with light : luminous

b

: translucent

snorkeling in the lucid sea

2

: having full use of one's faculties : sane

3

: clear to the understanding : intelligible

lucidly adverb

lucidness noun

Did you know?

Shine a Light on the Origin of Lucid

Let’s shine a light on lucid, an adjective whose senses of “shining” and “filled with light” reflect its roots in the Latin verb lucēre, meaning “to shine.” Lucid is also used to describe things that are visibly clear—that is, translucent (translucent being another lucēre descendent), as in “we enjoyed snorkeling in the lucid waters of the Caribbean.” Lucid is, however, most commonly applied in its figurative meanings where it can describe someone whose mind is clear, or something communicated with a clear meaning, as in “the author captured readers’ attention with her lucid prose,” and “the professor provided a lucid explanation of the topic.” Clearly, lucid has proven a useful and versatile word.

Synonyms

• luminous
• dazzling
• glowing
• shining
• bright
• radiant
• brilliant
• shiny

Choose the Right Synonym for lucid

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

Examples of lucid in a Sentence

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

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

"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

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

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

those lucid bands that spread across the arctic sky and are known as the northern lights

Recent Examples on the Web

By the parable-like broadness of its belief that love is the only thing lucid enough to see through an Orwellian assault on reality. —David Ehrlich, IndieWire, 28 Oct. 2025

And for those with certain mental health conditions, lucid dreaming on your own can sometimes make the condition worse. —Hannah Yasharoff, USA Today, 28 Oct. 2025

This mosaic can lead to experiences such as hypnagogia, lucid dreaming and sleep disorders. —Yasemin Saplakoglu, Quanta Magazine, 17 Oct. 2025

How much the reader should sympathize with Lisa—whether the character whom Harwicz has created is more aptly seen as a wronged person lashing out or as a more lucid villain—also feels unresolved. —Jessica Winter, New Yorker, 8 Oct. 2025

Word History

Etymology

borrowed from Latin lūcidus "bright, shining, light (of a place or time of day), clear to the understanding," adjective derivative, with the suffix -idus, corresponding to the verb lūcēre "to emit light, shine" — more at light entry 1

First Known Use

1591, in the meaning defined at sense 1a

Rhymes for lucid

• pellucid
• seleucid

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Kids Definition

lucid

adjective

lu·​cid ˈlü-səd 

1

a

: bright with light : luminous

b

: translucent sense 2

2

: having full use of one's reasoning ability : clear-minded

3

: clear to the understanding : plain

lucid writing

lucidity

lü-ˈsid-ət-ē

noun

lucidly

ˈlü-səd-lē

adverb

lucidness noun

Medical Definition

lucid

adjective

lu·​cid ˈlü-səd 

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

lucidity noun

plural lucidities