apples and oranges
Definition from Wiktionary, the free dictionary
Alternative forms 
- (idiomatic) Said of a comparison of items that are not comparable.
- It's apples and oranges. You can't convert square meters to linear inches.
- Comparing the grades of English students to Engineering students is like trying to compare apples and oranges.
- apples to apples, apples with apples
- apples to apples, oranges to oranges
- oranges with oranges (rare)
Related terms