1. having had ions removed; treated to remove dissolved mineral salts and ions
Usage: British spelling; American equivalent is 'deionized'; commonly used in chemistry and laboratory contexts

Examples

• The laboratory uses deionised water for all chemical experiments.
• Deionised water is essential for accurate pH measurements.
• We filtered the solution through a deionised resin to remove impurities.
• The battery requires deionised water to maintain proper function.
• Deionised water has a neutral pH and minimal conductivity.