seisin n.

mid-13c., seisen, "take possession, take possession of" (land, goods, etc.) by force or authority, from Old French seisir "to take possession of, take by force; put in possession of, bestow upon" (Modern French saisir), from Late Latin sacire (8c.), which generally is held to be from Germanic, but the exact source is uncertain. Perhaps from Frankish *sakjan "lay claim to" (compare Gothic sokjan, Old English secan "to seek;" see seek). Or perhaps from Proto-Germanic *satjan "to place" (see set (v.)).

Originally a legal term in reference to feudal property holdings or offices. Meaning "to grip with the hands or teeth" is from c. 1300; that of "to take possession by force or capture" (of a city, etc.) is from mid-14c. Figurative use, with reference to death, disease, fear, etc., "to come upon with a sudden attack," is from late 14c. Meaning "to grasp with the mind" is attested from 1855.

Of engines or other mechanisms, intransitive, "to stick, jam, lock fast," attested by 1878. Related: Seized; seizing.