fane n.

mid-13c., "garment, cloak, mantle; a part of a garment;" later "side of a building, section of a wall," from Old French pan "section, piece, panel" (11c.) and directly from Latin pannum (nominative pannus) "piece of cloth, garment," possibly from PIE root *pan- "fabric" (source also of Gothic fana "piece of cloth," Greek pēnos "web," Old English fanna "flag"). De Vaan writes, "If the Gr. and Gm. words listed are related, they probably represent loanwords from an unknown source."

From late 14c. as "section of a wall," also "ornamental hanging, coverlet," and c. 1400 as "a bedspread." The general notion in the word is "distinct part or piece of a surface." Sense of "piece of glass inserted in a window" is attested by mid-15c.

1590s, variant of Middle English gonfanon (c. 1300), from Old French gonfanon "knight's pennon" (12c., Modern French gonfalon), from Frankish *gundfano or Old High German guntfano "battle flag," from a Proto-Germanic compound of *gunthjo "war, battle" (from PIE *gwhen- "to strike, kill;" see bane) + *fano "banner" (compare Gothic fana "cloth;" see fane). Cognate with Old English guþfana, Old Norse gunnfani. Change of -n- to -l- by dissimilation.

"plate metal wind indicator," early 15c., southern England alteration (see V) of fane "flag, banner."