I know there’s a fixed phrase the day after tomorrow. But is it possible to omit the second tomorrow in the following sentence?
We won’t be meeting tomorrow and the day after [tomorrow].
You can omit the second tomorrow, but you’ve got the wrong conjunction in your sentence. It should read:
We won’t be meeting tomorrow or the day after.
By using tomorrow previously in the sentence, you’ve already implied it as the word after after. So that should be just fine.