| Subject | English | Catalan |
| math. | addition of variates | addició de variables |
| environ. | addition polymer A polymer formed by the chain addition of unsaturated monomer molecules, such as olefins, with one another without the formation of a by-product, as water; examples are polyethylene, polypropylene and polystyrene | polímer addicional |
| environ. | chemical addition Chemical reaction in which one or more of the double bonds or triple bonds in an unsaturated compound is converted to a single bond by the addition of other atoms or groups | addició |