A spiderweb is the network spun by a spider to catch its prey. It is described in Guillim’s Display of Heraldry, 1610 , and is considered compatible with period armory. The spiderweb is throughout by mundane and Society default; some blazons nonetheless blazon this fact explicitly. See also net.
The March of Grimfells bears: Sable, on a pile throughout Or a spiderweb throughout sable charged with a laurel wreath vert.
Helga Iden dohtir bears: Argent, a spiderweb azure.
Brangwayn Snowden bears: Quarterly Or and gules, a spiderweb counterchanged.