"situated outside or beyond the walls of," 1820, from extra- + ending from intermural.

"not belonging or proper to a thing; not intrinsic or essential, though attached; foreign," 1630s, from Latin extraneus "external, strange," literally "that is without, from without" (as a noun, "a stranger"), from extra "outside of" (see extra-). A doublet of strange. Related: Extraneously.

"being beyond or out of the common order or rule; not of the usual, customary, or regular kind," early 15c., from Latin extraordinarius "out of the common order," from extra ordinem "out of order," especially the usual order, from extra "out" (see extra-) + ordinem, accusative of ordo "row, rank, series, arrangement" (see order (n.)).

Of officials, etc., "outside of or in addition to the regular staff," often "temporarily employed for a specific purpose," from 1580s. Also from 1580s in the sense of "remarkable, uncommon, rare, wonderful." Related: Extraordinarily; extraordinariness.

"make an approximate calculation by inferring unknown values from trends in the known data," 1862 (in a Harvard observatory account of the comet of 1858), from extra- + ending from interpolate. Said in early references to be a characteristic word of Sir George Airy (1801-1892), English mathematician and astronomer. Related: Extrapolated; extrapolating.

"an approximate calculation made by inferring unknown values from trends in the known data," 1867, noun of action from extrapolate by analogy of interpolation. The original sense was "an inserting of intermediate terms in a mathematical series." The transferred sense of "drawing of a conclusion about the future based on present tendencies" is from 1889.

also extra-sensory, "beyond or not involving the usual senses," 1934, coined as part of extra-sensory perception in J.B. Rhine's work, from extra- + sensory. Extrasensible (1874) was used earlier in reference to "that which is inaccessible to the senses."

also extra-terrestrial, "occurring or originating outside the Earth," 1812, from extra- + terrestrial. As a noun from 1956.