From the Old High Germ. ecca, Mod. Germ. ecke, Ang.-Sax. ecg, edge, sharpness, cognate with Lat. acies, &c., and from the root found in Sasc. ag, ac, to pierce, I take the forms ag, ac, eg, ec, widely spread in proper names.  And I also include the forms hag, hac, though Old Norse hagr, handy, useful, might be suitable.  Grimm, however, explains the name Hagen as "spinosus."  Still it must be admitted that the varied forms of the group suggest the probability of an admixture of roots.  SIMPLE FORMS.  Old German Ago, Acco,... Old Norse Haki.  English Agg, Ague,...  Mod. German Acke, Egge, Ecke, Hacke,... (Ferguson)