I just came across this sentence -

"Scientists have long believed that comets and, or a type of very primitive meteorite called carbonaceous chondrites were the sources of early Earth's volatile elements -- which include hydrogen, nitrogen, and carbon -- and possibly organic material, too."

I was wondering what does "and, or" mean here? Does it mean either comets, or meteorite or both?

  • Probably means "comets and chondrites" but it's rather poorly written. – Martin F Oct 16 '18 at 5:08

Your assumption is correct; it does mean 'either or both.' However, it's normally written with a slash instead of a comma:


| improve this answer | |
  • 2
    And it is even more usually (and better) written "or". In most such cases, "or" means inclusive or (not XOR). – Drew Jun 28 '16 at 17:04
  • Using "not XOR" in everyday writing or speeches tends to confuse people. Even XOR is rare enough to cause problems. – Wayfaring Stranger Jun 28 '16 at 19:18

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.