D defs.my
Entry 2 senses Webster, 1913

In situ

· In si·tu · IPA /ɪnˈsɪ.t(j)uː/
01 adv. & adj. In its natural or original position or place; in position; -- said specif., in geology, of a rock, soil, or fossil, when in the situation …
  1. 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. 2.
    In its original position; not extending beyond the place of origin; localized and undisturbed; as, carcinoma in situ.(Med.)