Element
ion Audio
i·on [ ahy-uhn, ahy-on ]
Subclass of:
Electrolytes
Etymology:
Greek ion = going
Descriptive of the movement of charged particles.
Definitions related to ions:
  • An atom or a molecule that has a positive or negative electrical charge. Examples are sodium, potassium, calcium, chloride, and phosphate. These ions help move nutrients into cells, help move waste out of cells, and help nerves, muscles, the heart, and the brain work the way they should.
    NCI Dictionary of Cancer Terms
    U.S. National Cancer Institute, 2021
  • An atom or molecule having a positive or negative charge owing to the loss or gain of one or more electrons.
    NCI
    U.S. National Cancer Institute, 2021
  • Atom or radical having an electrical charge owing to the loss or gain of one or more electrons; substances that form ions are called electrolytes.
    CRISP Thesaurus
    National Institutes of Health, 2006
  • An atom or group of atoms that have a positive or negative electric charge due to a gain (negative charge) or loss (positive charge) of one or more electrons. Atoms with a positive charge are known as CATIONS; those with a negative charge are ANIONS.
    NLM Medical Subject Headings
    U.S. National Library of Medicine, 2025
Try this search on: Farlex, Merriam-Webster, Oxford Dictionary, or Wordnik

This content should not be used in place of medically-reviewed decision support reference material or professional medical advice. Some terms may have alternate or updated definitions not reflected in this set. The definitions on this page should not be considered complete or up to date.