based on custom rather than documentation; "an unwritten law"; "rites...so ancient that they well might have had their unwritten origins in Aurignacian times"- J.L.T.C.Spence
the convergence of two parallel railroad tracks in a narrow place; the inner rails cross and run parallel and then diverge so a train remains on its own tracks at all times
resist or confront with resistance; "The politician defied public opinion"; "The new material withstands even the greatest wear and tear"; "The bridge held"
elude, especially in a baffling way; "This behavior defies explanation"
a hostile meeting of opposing military forces in the course of a war; "Grant won a decisive victory in the battle of Chickamauga"; "he lost his romantic ideas about war when he got into a real engagement"
battle or contend against in or as if in a battle; "The Kurds are combating Iraqi troops in Northern Iraq"; "We must combat the prejudices against other races"; "they battled over the budget"