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”

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Example Sentences

See Examples For:

in situ

At UTK, Michael Koehler used in situ X-ray diffraction to follow changes in the phases of the reaction mixture as the chemistry unfolded.

From Science Daily ● Sep. 21, 2026

The obelisk was displaced to Paris, certainly, and the Rosetta Stone, also hitherto neglected in situ, went to Britain.

From The Wall Street Journal ● Sep. 12, 2026

In a recent study published in Nature Catalysis, researchers found that highly active structures can form in situ when the surface of NiO reconstructs during POM.

From Science Daily ● Sep. 9, 2026

He told The Sunday Show: "What I'm surprised to hear is that a government that has been in situ for 19 years still cannot put names and numbers around the reorganisation."

From BBC ● Sep. 6, 2026

Diagnosing carcinoma in situ had only been possible since 1941, when George Papanicolaou, a Greek researcher, published a paper describing a test he’d developed, now called the Pap smear.

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

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Related Words

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