Words that have the same prefix as pentagon?

Here are some words that have the same prefix as "pentagon," which is penta-:

* Pentad: A group of five.

* Pentameter: A line of poetry with five metrical feet.

* Pentagram: A five-pointed star.

* Pentathlon: An athletic competition consisting of five events.

* Pentavalent: Having a valence of five.

* Pentarchy: A government of five rulers.

* Pentateuch: The first five books of the Hebrew Bible.

* Pentacle: A five-pointed star used in ceremonial magic.

Let me know if you'd like more examples!