An Etymological Dictionary of Astronomy and Astrophysics

1. One of the divisions of a window or the like, consisting of a single plate of glass in a frame. A plate of glass for such a division.
   

2. A panel, as of a wainscot, ceiling, door, etc (Dictionary.com).

Etymology (EN): M.E. pane, pan “strip of cloth, section,” from M.Fr. pan,
from O.Fr. pan “section, piece, panel,” from L. pannum “piece of cloth, garment;” cf. Goth. fana “piece of cloth,” Gk. penos “web,” O.E. fanna “flag.”

Etymology (PE): Poš, from Baluci poc “cloth, clothing,” from puš-, pušidan “to cover, to wear,” → envelope.