atter:

From Middle English atter, ater, from Old English āttor, ?ttor, ātor ?(“poison”), from Proto-Germanic *aitr? ?(“gland, matter”), from Proto-Indo-European *ayd-, *oyd- ?(“tumor, abscess”). Cognate with Scots attir ?(“corrupt matter, pus”), Scots atter, etter ?(“poison, venom”), Saterland Frisian Atter ?(“pus”), Dutch etter ?(“pus”), German Eiter ?(“poison, pus”), Danish edder, ?dder ?(“venom”), Swedish etter ?(“poison, venom, virulence”), Norwegian eiter ?(“venom”), Icelandic eitur ?(“poison”).