tundish

Short definition from Wiktionary

Noun

1. 1
   A kind of funnel used in brewing fitting into the bung-hole of a tun or cask.
2. 2
   A funnel used in smelting, foundry work etc.
3. 3
   A funnel used to create a siphonic break in a drainage system and/or provide visual indication of flow, usually in an overflow line.