Interestingly, on that basis, it might be as well to recognise the pronunciation differences between the different meanings.
Where we mean a registered patent, the emphasis is on PAT as in the way we would say pat the dog, or Postman Pat, whereas the patent meaning open is pronounced PAY as in pay day, or payment.
I was using the word as an adjective, not a noun, so in that context I hope it is patently obvious that I meant the chimney was not open.
Much more important than this is who ate all the candy?