A cobweb is an abandoned spider web, usually extremely dusty and three-dimensional.
The Fire-Making Spell could be used to quickly incinerate both cobwebs and spider webs, as Miranda Goshawk noted in The Standard Book of Spells, Grade 2.
In the summer of 1995, 12 Grimmauld Place had a "cobwebby chandelier" and likely other cobwebs due to its general lack of upkeep.
On 1 September, 2017, the breath of the pedestrians outside of King's Cross Station was said to sparkle like cobwebs in the cold autumn air.
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