Ymb-trymming

According to the Old English Dictionary:

e;

ymb-trymming

f. A fortification :-- Ymbtrymming oððe fæstnys munimen, Ælfc. Gr. 9, 12; Zup. 41, 3. Ðíne fýnd ðé ymbsittaþ mid ymbtrymminge circtimdabunt te inimici tui uallo (Lk. 19, 43), Homl. Th. i. 408, 35. ymb-trymming