the.com/buttercream

means A rich frosting made by beating butter and sugar (often with eggs or milk) into a smooth, spreadable cream used to cover and decorate cakes.

from Simply a compound of 'butter' and 'cream' — a plainly descriptive English name rather than a borrowed or storied word. 'Butter' traces back through Old English 'butere' to Latin 'butyrum', itself likely from Greek 'boutyron' (possibly 'cow-cheese'); 'cream' comes via Old French 'cresme' from Late Latin 'cramum', a word of uncertain, possibly Gaulish, origin. The frosting itself is a far more modern invention than either word — the name just does exactly what it says.