cobweb – паутина

cobweb (n.) (из «coppewebbe»); первая часть из староанглийского «atorcoppe» - паук, дословно «голова + яд».
early 14c., coppewebbe; the first element is Old English -coppe, in atorcoppe "spider," literally "poison-head" (see attercop). Spelling with -b- is from 16c., perhaps from cob. Cob as a stand-alone for "a spider" was an old word nearly dead even in dialects when J.R.R. Tolkien used it in "The Hobbit" (1937).

cob (n.) (многозначимое слово) – куча, ком, круглый объект, так же «голова».
a word or set of identical words with a wide range of meanings, many seeming to derive from notions of "heap, lump, rounded object," also "head" and its metaphoric extensions. With cognates in other Germanic languages; of uncertain origin and development. "The N.E.D. recognizes eight nouns cob, with numerous sub-groups. Like other monosyllables common in the dial its hist is inextricable" . In the 2nd print edition, the number stands at 11. Some senses are probably from Old English copp "top, head," others probably from Old Norse kubbi or Low German, all perhaps from a Proto-Germanic base *kubb- "something rounded." Among the earliest attested English senses are "headman, chief," and "male swan," both early 15c., but the surname Cobb (1066) suggests Old English used a form of the word as a nickname for "big, leading man." The "corn shoot" sense is attested by 1680s.

web (n.) (паутина); из староанглийского «webb» - сотканная ткань; из протогерманского *wabjam – ткань, паутина; из PIE *webh- ткать, плести.
Old English webb "woven fabric," from Proto-Germanic *wabjam "fabric, web" (cf. Old Saxon webbi, Old Norse vefr, Dutch webbe, Old High German weppi, German gewebe "web"), from PIE *webh- "to weave" (see weave (v.)).

Как «куб» может быть круглым? Если только через латинское «caput» - голова. Интересно, где они ядовитых пауков в Англии нашли?
Итак, наша «купа», переросшая в латинскую «голову» + «вить». ВТ – замена «т» - «b» - WB – web.