| PI | Performance Index |
|---|---|
| PI | Permeability index |
| PI | Persistent infection |
| PI | Persistently infected |
| Pi | Phosphate ion |
| PI | Phosphatidylinositide |
| Pi | phosphocreatin , inorganic phosphates |
| PI | Phosphoinositide |
| PI | Phosphoinositol |
| Pi | Phosphomonoesters, inorganic phosphate |