GC: n

S: NCBI – https://pubmed.ncbi.nlm.nih.gov/1509814/ (last access: 15 August 2021); MEDNT – https://www.medicalnewstoday.com/articles/324330 (last access: 15 August 2021).

N: 1. 1580s, “a violent and involuntary contraction of the muscular parts of the body,” from Latin convulsionem (nominative convulsio) “cramp, convulsion,” noun of action from past-participle stem of convellere “to tear loose,” from assimilated form of com “with, together” + vellere “to pluck, pull violently”.
Meaning “any violent or irregular (social, political, etc.) motion, turmoil” is from 1640s. Of laughter, 1735. Related: Convulsions; convulsional.
2. 1 a : an abnormal violent and involuntary contraction or series of contractions of the muscles. 1 b : seizure (a sudden attack as of disease, especially: the physical manifestations -such as convulsions, sensory disturbances, or loss of consciousness- resulting from abnormal electrical discharges in the brain -as in epilepsy-). 2 a : a violent disturbance. 2 b : an uncontrolled fit: paroxysm.
3. A violent involuntary contraction or series of contractions of the voluntary muscles.
4. convulsion: term usually used in the plural.

S: 1. OED – https://www.etymonline.com/search?q=convulsion&ref=searchbar_searchhint (last access: 15 August 2021). 2. MW – https://www.merriam-webster.com/dictionary/convulsion (last access: 15 August 2021). 3&4. TERMIUM PLUS – https://www.btb.termiumplus.gc.ca/tpv2alpha/alpha-eng.html?lang=eng&i=1&srchtxt=convulsion&index=alt&codom2nd_wet=1#resultrecs (last access: 15 August 2021).

SYN: seizure (depending on context)

S: DRUGS – https://www.drugs.com/condition/seizures.html (last access: 15 August 2021)

CR: epilepsy