Calder, AlexanderCal‧der, Al‧ex‧an‧der /ˈkɔːldə, ˌælɪɡˈzɑːndə $ -dər, -ˈzændər/(1898–1976) a US sculptor best known for his large outdoor works of art found in many cities, and for his large mobiles (=decorations made of objects tied to wires or string which move when air blows around them)