An Etymological Dictionary of Astronomy and Astrophysics

1. An oval or round object laid by a female bird, reptile, fish, or invertebrate, usually containing a developing embryo. The eggs of birds are enclosed in a chalky shell, while those of reptiles are in a leathery membrane.
   

   2. Biology: The female reproductive cell in animals and plants; an ovum (OxfordDictionaries.com).

Etymology (EN): M.E., from Old Norse egg, cognate with O.Saxon, M.Du., Du., O.H.G., Ger. Ei, probably from PIE *owyo-/*oyyo- “egg;” source of Pers. xâg, as below.

Etymology (PE): Toxm, → seed.
Xâg “egg,” Lori, Laki xâ, Pash. hâ “egg,” Ossetic ajk “egg,” Bojnurdi hek “egg,” Khotanese āhaa- “egg;” variant xâyé “egg; testicle;” Mid.Pers. xâyak “egg;” Av. aēm/aiam “egg;” cf. Gk. oion, L. ovum; Goth. ada; O.E. æg; Ger. Ei; PIE *owyo-/*oyyo- “egg.”

1. An oval or round object laid by a female bird, reptile, fish, or invertebrate, usually containing a developing embryo. The eggs of birds are enclosed in a chalky shell, while those of reptiles are in a leathery membrane.
   

   2. Biology: The female reproductive cell in animals and plants; an ovum (OxfordDictionaries.com).

Etymology (EN): M.E., from Old Norse egg, cognate with O.Saxon, M.Du., Du., O.H.G., Ger. Ei, probably from PIE *owyo-/*oyyo- “egg;” source of Pers. xâg, as below.

Etymology (PE): Toxm, → seed.
Xâg “egg,” Lori, Laki xâ, Pash. hâ “egg,” Ossetic ajk “egg,” Bojnurdi hek “egg,” Khotanese āhaa- “egg;” variant xâyé “egg; testicle;” Mid.Pers. xâyak “egg;” Av. aēm/aiam “egg;” cf. Gk. oion, L. ovum; Goth. ada; O.E. æg; Ger. Ei; PIE *owyo-/*oyyo- “egg.”

The reappearance of a celestial body after an eclipse, an occultation, or a transit; same as emersion. → ingress.

Etymology (EN): From L. egressus, from egredi “to go out,” from → ex- “out”

• -gredi, comb. form of gradi “to walk, go, step;” from PIE *ghredh- (cf. Lith. gridiju “to go, wander,” O.C.S. gredo “to come”).

Etymology (PE): Osgâm “going out,” from os- “out,” → ex-, + gâm “step, pace,” Mid.Pers. gâm, O.Pers. gam- “to come; to go,” Av. gam- “to come; to go,” jamaiti “goes,” Mod.Pers. âmadan “to come,” Skt. gamati “goes,” Gk. bainein “to go, walk, step,” L. venire “to come,” Tocharian A käm- “to come,” O.H.G. queman “to come,” E. come; PIE root *gwem- “to go, come.”

The reappearance of a celestial body after an eclipse, an occultation, or a transit; same as emersion. → ingress.

Etymology (EN): From L. egressus, from egredi “to go out,” from → ex- “out”

• -gredi, comb. form of gradi “to walk, go, step;” from PIE *ghredh- (cf. Lith. gridiju “to go, wander,” O.C.S. gredo “to come”).

Etymology (PE): Osgâm “going out,” from os- “out,” → ex-, + gâm “step, pace,” Mid.Pers. gâm, O.Pers. gam- “to come; to go,” Av. gam- “to come; to go,” jamaiti “goes,” Mod.Pers. âmadan “to come,” Skt. gamati “goes,” Gk. bainein “to go, walk, step,” L. venire “to come,” Tocharian A käm- “to come,” O.H.G. queman “to come,” E. come; PIE root *gwem- “to go, come.”