Definition
Said of things that are very different, though possibly superficially alike.
Origins
Attested in variant form since 1393. The surface of some cheeses, particularly unaged ones, resembles the surface of chalk: white, crumbling, but in substance cheese is much softer than chalk. It is interesting to note that lime chalk and cottage cheese forms a glue-like material used in the restoration of ancient half-timbered houses, perhaps suggesting an alternative original meaning.
Also Said As
- apples and oranges
- day and night
- night and day
How People Actually Use It
Two things that might be confused as similar but which are in fact very different.
"Fedora and Ubuntu are like chalk and cheese."
Source: Urban Dictionary