c. 1600, "that which supplies a want or need," from French accommodation, from Latin accommodationem (nominative accommodatio) "an adjustment," noun of action from past-participle stem of accommodare "make fit; make fit for" (see accommodate).
Meaning "appliance, anything which affords aid" is from 1610s; that of "act of accommodating" is from 1640s. Meaning "arrangement of a dispute" is from 1640s. An accommodation train (1838) was one making all stops (as opposed to an expresss); it was used earlier of stages (1811).