oxidize

verb

1. (transitive)To combine with oxygen or otherwise make an oxide.

   “Oxygen levels on Earth skyrocketed 2.4 billion years ago, when cyanobacteria evolved photosynthesis:[…]. The evolutionary precursor of photosynthesis is still under debate, and a new study sheds light. The critical component of the photosynthetic system is the “water-oxidizing complex”, made up of manganese atoms and a calcium atom.”

2. To increase the valence (or the positive charge) of an element by removing electrons.
3. To coat something with an oxide.
4. (intransitive)To become oxidized.