The usual spelling is possum in everyday use, but opossum is also correct, especially in scientific or formal writing. For the North American animal, opossum is the more precise term, while possum is the common casual spelling.

Quick scoop

  • Common spelling: possum.
  • Formal/scientific spelling: opossum.
  • Common mistake: spelling it with two p’s, like possom.
  • Plural: possums or opossums, depending on which word you use.

Easy rule

If you just want the simple, everyday word, use possum. If you’re writing more formally about the North American marsupial, use opossum.