Dialectal variant of expected Raum (early modern German, rare), from Middle High German roum, from Old High German roum, from Proto-Germanic *raumaz. The form Rahm ousted the regular form due to homonymy with Raum (“room”), from Middle High German rūm. Dialects that have developed Middle High German -ou- into -ā- are found in south-eastern and central-western Germany. Cognate with Dutch room and English ream.
Rahm m (genitive Rahmes, no plural)
- cream (milkfat)
- In German standard German, Rahm is used mainly in compounds (such as Rahmsoße, Sauerrahm etc.); otherwise Sahne is much more common. This is not necessarily true of colloquial varieties nor of standard German in Austria and Switzerland.
- Creme (“cream” in the sense of “frosting”)
- Rahm in Duden online