An Etymological Dictionary of Astronomy and Astrophysics

Having relatively little extent from one surface or side to the opposite; not thick. → optically thin; → superthin galaxy.

Etymology (EN): M.E. thyn(ne), O.E. thynne, from P.Gmc. *thunnuz, *thunw- (cf. W.Fris. ten, M.L.G. dunne, Du. dun, O.H.G. dunni, Ger. dünn), from PIE *tnus-, *tnwi-, from base *ten- “stretch;” cf. Pers. tonok “thin, slender,” → attenuate.

Etymology (PE): Nâzok, from Mid.Pers. nâzuk, nâzik “tender, gentle.”