What Does It Mean?

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From our dictionary:
in si•tu

(in sī'tOO, -tyOO, sē'-; Latin. in sit'OO),
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. Med.
a. in place or position;
b. in a localized state or condition: carcinoma in situ.