It comes from the Greek word "περί" (peri), which means "around", "about", or "near".
Many English words with "peri-" in them have Greek origins, such as:
* Perimeter (the outer boundary of a two-dimensional figure)
* Periscope (a device for viewing from a concealed position)
* Periphery (the outer limits or edge of something)
* Periodical (published at regular intervals)