in situ

adverb or adjective

in si·​tu (ˌ)in-ˈsī-(ˌ)tü How to pronounce in situ (audio)
-ˈsi-,
-(ˌ)tyü How to pronounce in situ (audio)
 also  -ˈsē-,
-(ˌ)chü How to pronounce in situ (audio)
: in the natural or original position or place
an in situ cancer confined to the breast duct

Examples of in situ in a Sentence

Recent Examples on the Web Harvard's Conroy was part of a team that measured the in situ stars' chemistry and found two populations: one group was ancient, metal-poor, moving chaotically and forming stars slowly; the other was younger, metal-rich, moving coherently and forming stars 10 times faster. Ann Finkbeiner, Scientific American, 16 Jan. 2024 Yet some might have seen the weather forecast and decided on spending their afternoon elsewhere in one of Europe's cultural capitals, and there were spells of the game were those in situ left their seats to take cover through intervals of heavy rain. Tom Sanderson, Forbes, 25 Feb. 2024 The engraved sandstone boulder in this case—found during rock art surveys—was studied in situ and dated to around 8,000 years ago. Kyle Orland, Ars Technica, 2 Jan. 2024 Thus, the technology may first be tested on the Moon, to generate electrical power in situ for use with forthcoming lunar habitats and colonization efforts. Bruce Dorminey, Forbes, 29 Nov. 2023 Clear indicators of high risk come from a biopsy showing abnormal growths: proliferative lesions or premalignant lesions in the breast such as atypical hyperplasia or lobular carcinoma in situ, or LCIS. Elizabeth Cooney, STAT, 13 Nov. 2023 The drill will retrieve soils from ancient parts of Mars and analyse them in situ with its onboard laboratory. IEEE Spectrum, 15 Dec. 2023 Shipping supplies from Earth is expensive and inconvenient, so in situ production is preferred whenever possible. Elizabeth Rayne, Ars Technica, 27 Oct. 2023 Mixed shades of clashing colors and geometric patterns presented as wearable art in situ. Zachary Schwartz, Vogue, 2 Nov. 2023

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'in situ.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

Latin, in position

First Known Use

1740, in the meaning defined above

Time Traveler
The first known use of in situ was in 1740

Dictionary Entries Near in situ

Cite this Entry

“In situ.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/in%20situ. Accessed 19 Mar. 2024.

Kids Definition

in situ

adverb or adjective
in si·​tu (ˈ)in-ˈsī-t(y)ü How to pronounce in situ (audio)
-ˈsi-
: in the natural or original position
the cancer cells remained in situ
Etymology

Latin, "in position"

Medical Definition

in situ

adverb or adjective
in si·​tu
(ˈ)in-ˈsī-(ˌ)t(y)ü, -ˈsi- also -ˈsē-, -(ˌ)chü
: in the natural or original position or place
an in situ cancer confined to the breast duct
see carcinoma in situ
Last Updated: - Updated example sentences
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