Magna Carta UK /ˌmæɡnə ˈkɑːtə/US /ˌmæɡnə ˈkɑːɹtə/ noun1 •(figurative) A landmark document that sets out rights or important principles.[R]egarding this new Ordinance relating to the trade union movement, we on the workers' side will consider it as the Magna Carta of the trade union movement and for the workers in Singapore. — 1959 formsMagna Cartas