rapuvoi

Noun

 * 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.

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