elastic, machine-made fabric used for undergarments, 1824, from stocking + diminutive ending -et.
Entries linking to stockinet
stocking n.
"close-fitting garment covering the foot and lower leg," 1580s, from stock "leg covering, stocking" (late 15c.), from Old English stocu "sleeve," related to Old English stocc "trunk, log" (see stock (n.1)). Probably so called because of a fancied resemblance of legs to tree trunks, or a reference to the punishing stocks. Cognates include Old Norse stuka, Old High German stuhha, from the same Proto-Germanic source. Restriction to women's hose is 20c. As a receptacle for Christmas presents, attested from 1853; hence stocking stuffer first recorded 1945. Stocking-feet "without shoes" is from 1802.
-et
word-forming element, originally a diminutive suffix but not now always felt as one, Middle English, from Old French -et (fem. -ete; Modern French -et, -ette), from Vulgar Latin *-ittum/*-itta (source also of Spanish -eto/-eta, Italian -etto/-etta), of unknown origin. The French forms are reduced to -et in English, but later borrowings of French words in -ette tend to keep that ending.