ion
[C] Countable
pl: ions
This term belongs to the specialized language of chemistry and physics, carrying a clinical and precise tone. It describes a state of instability or imbalance, where an entity has deviated from its neutral electrical state to become either positive or negative. In modern marketing, the word has drifted into a pseudo-scientific buzzword. You will often see it in beauty products or air purifiers to imply a high-tech, purifying, or energizing effect, even when the actual science is negligible.
Countable when referring to individual charged particles in a chemical reaction or a plasma.