Field glossaryWeirThe downstream lip of the trap where water spills over toward the drainUsed across 2 Anvilfield field guides, most in Plumbing. Where this shows upPlumbingPlumbing traps and trap seal guidePlumbingDWV venting and pipe sizing guide Related termsTrap armTrap sealAAVDeveloped lengthDFUDry ventTrapTrap primer Back to the full field glossary