electrolyte

Solution or molten substance in which an electric current is made to flow by the movement and discharge of ions in accordance with Faraday's laws of electrolysis.

The term ‘electrolyte’ is frequently used to denote a substance that, when dissolved in a specified solvent, usually water, dissociates into ions to produce an electrically conducting medium.

In medicine the term is often used for the ion itself (sodium or potassium, for example). Electrolyte balance may be severely disrupted in illness or injury.