lacuna

noun

la·​cu·​na lə-ˈkü-nə  -ˈkyü- 

plural lacunae lə-ˈkyü-(ˌ)nē  -ˈkü-ˌnī  also lacunas lə-ˈkü-nəz 

-ˈkyü-

1

: a blank space or a missing part : gap

the evident lacunae in his story

—Shirley Hazzard

also : deficiency sense 1

despite all these lacunae, those reforms were a vast improvement

—New Republic

2

: a small cavity, pit, or discontinuity in an anatomical structure

lacunar

lə-ˈkü-nər  -ˈkyü- 

adjective

or less commonly lacunate

lə-ˈkü-nət 

-ˈkyü-,

-ˌnāt;

ˈla-kyə-ˌnāt

Did you know?

If you find yourself drawing a blank when it comes to the definition of lacuna, it might help to imagine drawing water instead, ideally from a lake or lagoon. Lacuna, lake and lagoon all come ultimately from lacus, the Latin word for “lake.” Latin speakers modified lacus into lacuna to form a word meaning “pit,” “gap,” or “pool.” When English speakers borrowed the term in the 17th century, they used it to refer to a figurative gap in or missing portion of something, such as information or text. (Note that lacuna comes with two plural options: the Latin lacunae \luh-KYOO-nee\ or \luh-KOO-nye\ or the anglicized lacunas \luh-KOO-nuz\.) Lagoon, meanwhile, hewed closer to the Latin lacuna, referring first to a shallow sound, channel, or pond near or connected to a larger body of water, and later to a shallow artificial pool or pond.

Synonyms

• shortage
• lack
• deficiency

Examples of lacuna in a Sentence

She found a lacuna in the historical record.

attributes many of the nation's problems to a lacuna of leadership at the top

Recent Examples on the Web

As for a biography of Talking Heads, we are still left with a lacuna that Gould has unfortunately not filled. —Marc Weingarten, Los Angeles Times, 17 June 2025

At the heart of every biography, though, lies a lacuna—something unknowable, no matter how candid or heavily documented the subject, no matter how familiar or diligent the biographer. —Casey Cep, New Yorker, 14 Apr. 2025

The experience attempts to recall lacunas or lost memories, yet in trying to remember, temporalities and subjectivities become muddled and new thoughts, ideas, and images form in the viewer’s mind. —Mariana Fernández, ARTnews.com, 18 Dec. 2024

The country is still waiting for its first win in the international category, a lacuna that adds even more pressure to the annual selection process. —Naman Ramachandran, Variety, 23 Sep. 2024

Word History

Etymology

Latin, pool, pit, gap — more at lagoon

First Known Use

1652, in the meaning defined at sense 1

Rhymes for lacuna

• calluna
• laguna
• tribuna
• varuna
• vicuna
• kuna
• luna
• tuna

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Medical Definition

lacuna

noun

la·​cu·​na lə-ˈk(y)ü-nə 

plural lacunae -ˈkyü-(ˌ)nē  -ˈkü-ˌnī  also lacunas -ˈk(y)ü-nəz 

: a small cavity, pit, or discontinuity in an anatomical structure: as

a

: one of the follicles in the mucous membrane of the urethra

b

: one of the minute cavities in bone or cartilage occupied by the osteocytes

lacunar

-ˈk(y)ü-nər 

adjective