Webster's Revised Unabridged Dictionary · 1913

In situ

In situ , adv. & adj.

[Latin]

1.
In its natural or original position or place; in position; -- said specif., in geology, of a rock, soil, or fossil, when in the situation in which it was originally formed or deposited.
2.
(Medicine) In its original position; not extending beyond the place of origin; localized and undisturbed; as, carcinoma in situ.

in-situ , adjective

being in the original position; not having been moved or transferred to another location; as, an in-situ investigator.