An Etymological Dictionary of Astronomy and Astrophysics

Math.: Of an ordered collection of terms, having the property that each term is contained in the preceding one. → nested function, → nested multiplication.

Etymology (EN): From nest, from M.E., O.E. nest “bird’s nest;”
cf. M.L.G., M.Du. nest, Ger. Nest, ultimately from PIE *nizdo- (cf. Skt. nidah “resting place, nest,” L. nidus “nest,” O.C.S. gnezdo, O.Ir. net, Breton nez “nest”), probably from → ni- (PIE) + *sed- “sit” (cf. Pers. nešastan “to sit”), → lander.

Etymology (PE): Tu-dar-tu literally “inside in inside,” from tu “inside, in;” dar, → in-.