| OPO | an odorous gum resin formerly used in medicines |
|---|---|
| OPO | port city in northwest Portugal |
| OPO | nocturnal arboreal marsupial having a naked prehensile tail found from southern North America to northern South America |
| OPO | small furry Australian arboreal marsupials having long usually prehensile tails |
| OPO | terrestrial marsupials of southern South America that resemble shrews |
| OPO | shrimp-like crustaceans whose females carry eggs and young in a pouch between the legs |
| OPO | medium-sized tree of West Virginia to Florida and Texas |