Merkishöfuðverkum
Merkishöfuðverkum is a term that appears in Old Norse texts, particularly in sagas and Eddic poetry. It translates roughly to "remarkable headaches" or "notable head pains." The exact nature and meaning of merkishöfuðverkum are subject to interpretation due to the limited and often metaphorical context in which it is used. It is not a medical diagnosis in the modern sense but rather a literary device.
In its literary usage, merkishöfuðverkum can denote a severe or significant headache experienced by a character.