in situ

American  

[in sahy-too, -tyoo, see-, in sit-oo] / ɪn ˈsaɪ tu, -tju, ˈsi-, ɪn ˈsɪt u /

adverb

1. situated in the original, natural, or existing place or position.

   The archaeologists were able to date the vase because it was found in situ.

2. Medicine/Medical.

   1. in place or position; undisturbed.

   2. (especially of a malignant tumor) in a localized state or condition.

      carcinoma in situ.

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in situ British  

/ ɪn ˈsɪtjuː /

adverb

1. in the natural, original, or appropriate position

2. pathol (esp of a cancerous growth or tumour) not seen to be spreading from a localized position

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in situ Cultural  

1. In the original place or arrangement: “The body was left in situ until the police arrived.” From Latin, meaning “in position.”

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Etymology

Origin of in situ

First recorded in 1730–40, in situ is from Latin in sitū literally, “in place”

Example Sentences

See Examples For:

in situ

To determine how the system worked, the researchers combined in situ spectroscopy, photochemical analysis, finite element simulations, and theoretical calculations.

From Science Daily ● Aug. 6, 2026

Some goods were left in situ, including a fitted home library which was partly paid for with SNP funds, a wooden library ladder, a kitchen unit for the boiler, and fitted mats in the hallway.

From BBC ● Jun. 23, 2026

More recently, I tidied the home of a friend who was in the hospital, the pill bottles and crumpled blankets left in situ as evidence of someone else’s pain.

From Los Angeles Times ● May 28, 2026

As for the Mother Tree Project, it found that the more towering beauties left in situ, the better for all types of seedlings and plants in the test sites.

From The Wall Street Journal ● Apr. 17, 2026

He also hoped to prove that women with carcinoma in situ needed aggressive treatment, so their cancer didn’t become invasive.

From "The Immortal Life of Henrietta Lacks" by Rebecca Skloot

Related Words

• situated