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).
Old English hlæder "ladder, steps," from Proto-Germanic *hlaidri (source also of Old Frisian hledere, Middle Dutch ledere, Old High German leitara, German Leiter), from suffixed form of PIE root *klei- "to lean" (source also of Greek klimax "ladder"). In late Old English, rungs were læddrestæfæ and the side pieces were ledder steles. The belief that bad things happen to people who walk under ladders is attested from 1787, but its origin likely is more scientific than superstitious.
1796, echellon, "step-like arrangement of troops," from French échelon "level, echelon," literally "rung of a ladder," from Old French eschelon, from eschiele "ladder," from Late Latin scala "stair, slope," from Latin scalae (plural) "ladder, steps," from PIE *skand- "to spring, leap" (see scan (v.)). Sense of "level, subdivision" is from World War I.
"fireman's scaling ladder," short for pompier ladder (by 1893), French, literally "fireman," from pompe "pump" (see pump (n.1)).
1650s, "resembling a ladder," from Latin scalaris "of or pertaining to a ladder," from scalae (plural) "ladder, steps, flight of steps" (see scale (n.2)). The noun in the mathematical sense of "a real number" is from 1846, coined by Irish mathematician William R. Hamilton (1805-1865), who can explain why it is the correct word for that.
"lodgings and entertainment," 1722, plural of accommodation, which is attested from c. 1600 as "room and provisions, lodging."
early 14c., "encampment;" late 14c., "temporary accommodation; place of residence," verbal noun from lodge (v.). Related: Lodgings.