1. A device or substance that removes ions from water or another liquid, typically used to produce deionized water for laboratory, industrial, or household purposes.
Usage: Also spelled 'deionizer' in U.S. English; Common in scientific and industrial contexts

Examples

• The laboratory uses a deioniser to prepare ultrapure water for chemical experiments.
• A deioniser cartridge needs to be replaced when it becomes saturated with ions.
• The deioniser removes both positive and negative ions from tap water.
• Industrial facilities often install large deionisers to treat water for manufacturing processes.
• You can buy a small deioniser for your home aquarium to improve water quality.