1839, "arrangement (of a building, etc.) to face east or any other specified direction," noun of action from orient (v.). Meaning "process of determining the points of the compass is by 1868, hence the extended sense of "action of determining one's mental bearings," with reference to new ideas, etc. (1870). Meaning "introduction to a situation" is from 1942. Sense of "the position or arrangement (of something) relative to the points of the compass" is from 1875. Related: Orientational.