Ge-twisa

According to the Old English Dictionary:

an;

ge-twisa

m. A twin :-- Twegen getwisan two twins, Gen. 38, 27: Swt. A. S. Rdr. 62, 197. Getwisan gemini, Ælfc. Gr. 13; Som. 16, 13: Bd. de nat. rerum; Wrt. popl. science 7, 5; Lchdm. iii. 244, 24. ge-twisa