| Subject | English | Basque |
| environ. | biochemical oxygen demand The amount of oxygen used for biochemical oxidation by a unit volume of water at a given temperature and for a given time. BOD is an index of the degree of organic pollution in water | OEB |
| environ. | chemical oxygen demand The quantity of oxygen used in biological and non-biological oxidation of materials in water; a measure of water quality | OEK |
| environ. | oxygen content Amount of oxygen contained in a solution | oxigeno-eduki |
| environ. | oxygen deficiency No definition needed | oxigeno-falta |