Hærn

According to the Old English Dictionary:

hærn

or hærne [?], es; m. n? The brain :-- It gæde tó ðe hærnes it went to the brains, Chr. 1137; Erl. 262, 6. [Prompt. Parv. henrys or brayne cerebrum; herne panne of þe hed craneum : Icel. hjarni; m : O. H. Ger. hirni; n. cerebrum : Ger. hirn; n.] hærn