rapuvoi

rapu (“crayfish, crab”) +‎ voi (“butter”)

rapuvoi

1. crab butter (greasy yellow-to-white jelly-like substance that accumulates on the inside of the shell of a crayfish or a crab)
2. tomalley, also crab butter (hepatopancreas of a crayfish when consumed as food, considered as delicacy by many, especially in Sweden and coastal Finland)
3. Butter flavored by simmering it with crayfish shells, used e.g. as base for soups.

The second sense ("hepatopancreas") may be considered erroneous, as there's a separate Finnish term maksahaima for it. The error derives from Swedish, as this part of the crayfish is often called kräftsmör in Swedish, which translates directly to rapuvoi. See also Swedish Wikipedia on Kräftsmör.

• maksahaima