- an electrically charged atom or group of atoms formed by the loss or gain of one or more electrons, as a cation (positive ion ), which is created by electron loss and is attracted to the cathode in electrolysis, or as an anion (negative ion ), which is created by an electron gain and is attracted to the anode. The valence of an ion is equal to the number of electrons lost or gained and is indicated by a plus sign for cations and a minus sign for anions, thus: Na+, Cl−, Ca++, S=.
- one of the electrically charged particles formed in a gas by electric discharge or the like.
- the eponymous ancestor of the Ionians: a son of Apollo and Creusa who is abandoned by his mother but returns to become an attendant in Apollo's temple at Delphi.
- a drama on this subject (415? b.c.) by Euripides.
- a suffix, appearing in words of Latin origin, denoting action or condition, used in Latin and in English to form nouns from stems of Latin adjectives (communion; union), verbs (legion; opinion), and especially past participles (allusion; creation; fusion; notion; torsion).
- Ionic.
- an electrically charged atom or group of atoms formed by the loss or gain of one or more electrons
- indicating an action, process, or state
