Ymb-setenness

According to the Old English Dictionary:

e;

ymb-setenness

f. Besieging, siege :-- Ðæt hý sceoldon ðam Gode þancian ðe hý gefriðode fram ðære ymbsetennesse, and fram ðære hergunge ðara twéga kynincga, Ps. Th. 45, arg. ymb-setenness