Nope, that wasn't a misspelling. That was ignorance of a term you heard or read but don't understand.
I agree that that alone doesn't indicate dementia. But such mistakes or errors or whatever you wish to call them are getting more and more frequent for you. Your mind is slipping. And I understand why you're so angry all the time. I'd like to think you weren't always this way. But feeling your mind and body slowly fall apart is a terrible thing. You have my sympathy.