ap·o·them 
(ăpə-thĕm′)
(ăpə-thĕm′)n.
The perpendicular distance from the center of a regular polygon to any of its sides.
[APO- + Greek thema, something laid down; see THEME.]
- protoplanet
- protoplanetary disk
- protoplasm
- protoplasmal
- protoplasmatic
- protoplasmic
- protoplast
- protoplastic
- protoporphyrin
- protostar
- protostele
- protostelic
- protostome
- prototroph
- prototrophic
- prototrophy
- prototypal
- prototype
- prototypic
- prototypical
- protozoal
- protozoan
- protozoic
- protozoological
- protozoologist