anschluss (n.)

1924 as a German word in English, from German Anschluß, "connection; addition; junction," literally "joining, union," from anschließen "to join, annex," from an "at, to, toward" (from Old High German ana- "on;" see on) + schließen "to shut, close, lock, bolt; contract" (a marriage); see slot (n.2). Specifically the Pan-Germanic proposal to unite Germany and Austria, accomplished in 1938.