オーメダル
A general term referring to the transformation items used in [[Kamen Rider OOO]]. The components that make up a Greeed and as a representation of desire and greed, O medals are classified in two categories: Core Medal and Cell Medal.

Core Medals are what makes up a Greeed and comes in three types: Head, Body, and Legs. These medals are what Hino Eiji uses to transform into [[Kamen Rider OOO]].

Cell Medals are the manifestation of human desire and make up the body of a Greeed and Yummy. These are used for the technology developed by the Kougami Foundation as well as the transformation item used by [[Kamen Rider Birth]]. 

For another explanation, the character Ankh explains that the medals are like a popsicle in the sense that Cells are what makes the ice cream part of a popsicle and Cores are the stick to keep it together.
o medal