Main Entry: an·gio·blast Pronunciation: 'an-jE-&-"blast Function: noun 1: one of the extraembryonic mesenchyme cells thatdifferentiate into the endothelium of the embryonic blood vessels 2: the mesenchymal tissue that gives rise to embryonic blood cells and blood vessels —an·gio·blas·tic/"an-jE-&-'blas-tik/adjective