Give both forms of the prefix meaning outside of.

The prefix meaning "outside of" can be represented in two forms: "extra-" and "exo-".

1. "Extra-" is a Latin prefix meaning "outside" or "beyond". For example, in the word "extraterrestrial", "extra-" means "outside" and "terrestrial" means "earth". So, "extraterrestrial" means "outside earth" or "beyond earth".

2. "Exo-" is a Greek prefix also meaning "outside" or "external". For example, in the word "exoskeleton", "exo-" means "outside" and "skeleton" means "structure". So, "exoskeleton" means "outside structure" or "external structure".