in situ

UK: /ˌɪnˈsɪtjuː/

US: /ɪn ˈsaɪtu, -tju, ˈsi-/

US: (in sī′to̅o̅, -tyo̅o̅, sē′-; Latin. in sit′o̅o̅)

WordReference Random House Learner's Dictionary of American English © 2026

in si•tu /ɪn ˈsaɪtu, -tyu, ˈsi-/  adj., adv. 

1. Foreign Terms situated in its original or natural place or position.

WordReference Random House Unabridged Dictionary of American English © 2026

in si•tu  (in sī′to̅o̅, -tyo̅o̅, sē′-; Latin. in sit′o̅o̅), 

1. Foreign Terms 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
   • in place or position;
     undisturbed.
   • in a localized state or condition:
     carcinoma in situ.

• Latin in sitū literally, in place
• 1730–40

Collins Concise English Dictionary © HarperCollins Publishers::

in situ / ɪn ˈsɪtjuː/ adverb , adjective (postpositive)

1. in the natural, original, or appropriate position