An Etymological Dictionary of Astronomy and Astrophysics

1. General: A relatively thin external form covering a hollow space.
   

2. The hard exterior of an egg; a hard outer covering of an animal, such as a mollusk.
   

3. Physics: → electron shell.
   

4. → seashell.
   

5. Astro.: → shell burning; → shell galaxy; → shell star; → shellular rotation; → SNR shell.

Etymology (EN): M.E.; from O.E. scell, sciell; cognate with Dutch schil “peel, skin,” O.Norse skel “shell,” from PIE root *(s)ker “to cut,” → bark.

Etymology (PE): Pusté “shell,” from pust “skin;” Mid.Pers. pôst “skin;” O.Pers. pavastā- “thin clay envelope used to protect unbaked clay tablets;” Av. pastô-, in pastô.fraθanhəm “of the breadth of the skin;” Skt. pavásta- “cover,” Proto-Indo-Iranian pauastā- “cloth.”
Pukel, from (Nahâvand, Hamadân, Ilâm) pukel “egg shell,” (Kurd.) tukel, probably (prefixed) from PIE root (s)ker- “to cut,” → bark, → scalp.