dagger: [14] Dagger has an uncertain history. There was a verb dag in Middle English, meaning ‘stab’, which suggests that dagger may simply be ‘something that stabs’, but similarity of form and sense indicates a connection too with Old French dague ‘dagger’. This appears to have come via Old Provençal or Old Italian daga from a hypothetical Vulgar Latin *daca, which meant literally ‘Dacian knife’ (from Latin Dācus ‘Dacian’). Dacia was the ancient name for an area roughly corresponding to modern Romania. [dagger etymology, dagger origin, 英语词源]