Migraine /mai· grein/

A migraine is a primary headache disorder characterized by recurrent headaches that are moderate to severe.[1] Typically, the headaches affect one half of the head, are pulsating in nature, and last from a few hours to 3 days.[1] Associated symptoms may include nausea, vomiting, and sensitivity to light, sound, or smell.[2] The pain is generally made worse by physical activity.[12] Up to one-third of people affected have an aura: typically a short period of visual disturbance that signals that the headache will soon occur.[12] Occasionally, an aura can occur with little or no headache following it.[13]

Migraines are believed to be due to a mixture of environmental and genetic factors.[3] About two-thirds of cases run in families.[5] Changing hormone levels may also play a role, as migraines affect slightly more boys than girls before puberty and two to three times more women than men.[4][14] The risk of migraines usually decreases during pregnancy and after menopause.[4][15] The underlying mechanisms are not fully known.[15] They are, however, believed to involve the nerves and blood vessels of the brain.[5]

Initial recommended treatment is with simple pain medication such as ibuprofen and paracetamol (acetaminophen) for the headache, medication for the nausea, and the avoidance of triggers.[10] Specific medications such as triptans or ergotamines may be used in those for whom simple pain medications are not effective.[5] Caffeine may be added to the above.[16] A number of medications are useful to prevent attacks including metoprolol, valproate, and topiramate.[8][9]

Globally, approximately 15% of people are affected by migraines.[11] It most often starts at puberty and is worst during middle age.[1] As of 2016, it is one of the most common causes of disability.[17] An early description consistent with migraines is contained in the Ebers papyrus, written around 1500 BCE in ancient Egypt.[18] The word migraine is from the Greek ἡμικρανία (hemikrania), 'pain in half of the head',[19] from ἡμι- (hemi-), 'half', and κρανίον (kranion), 'skull'.[20]

Ref: Wikipedia

1) migraine
noun [ C ]
UK
/ˈmiː.ɡreɪn/ /ˈmaɪ.ɡreɪn/ US
/ˈmaɪ.ɡreɪn/

severe continuous pain in the head, often with vomiting and difficulty in seeing:
Do you suffer from migraines?
Considering the amount of stress she's under, it's not surprising she keeps getting migraines.
a migraine headache