Final answer:
Alfred Wegener named the giant prehistoric landmass 'Pangaea,' proposing it as part of his continental drift theory.
Step-by-step explanation:
Alfred Wegener, the famed German meteorologist and astronomer who developed the theory of continental drift, referred to the ancient giant landmass as Pangaea.
Wegener proposed the idea of Pangaea, meaning "all land" in Greek, to explain the observed evidence that continents such as South America and Africa may have once been joined.
His hypothesis was based on the congruence of continental shapes and the similarities between fossils and living species found across these divided continents, suggesting that they were once part of a super continent.