Ceaster-æsc

According to the Old English Dictionary:

es;

ceaster-æsc

m. Black hellebore; helleborus niger :-- Wyrc gódne drenc ceasteræsces make a good drink of black hellebore, L. M. 3, 30; Lchdm. ii. 324, 20; Nim ceasteræsc take black hellebore, Lchdm. iii. 28, 20: 30, 14: 56, 15. ceaster-æsc