These words sound the same, but they have different meanings:
Air can be a noun or a verb and has several meanings. As a noun, it often refers to the gases we breathe or the open space above the ground. As a verb, one common meaning is ‘expose something to the air’.
Heiris always a noun and refers to someone who receives an inheritance.
Since ‘heir’ only has one meaning, it should be easy to remember. But if you need to tell these spellings apart, keep in mind that the ‘air’ we breathe is part of the ‘atmosphere’ and that both of these words begin with ‘a’.
And don’t forget: if you are worried about misusing these words, or any other aspect of your writing, our proofreading experts are here to help.