word-forming element attached to verbs, making nouns of state, condition, or action, from French -ion or directly from Latin -ionem (nominative -io, genitive -ionis), common suffix forming abstract nouns from verbs.
"positively charged ion," 1834, from Latinized form of Greek kation "going down," neuter present participle of katienai "to go down," from kata "down" (see cata-) + ienai "to go" (from PIE root *ei- "to go"). Proposed by the Rev. William Whewell, English polymath, and published by English physicist Michael Faraday. Compare ion.
syllable formed when the word-forming element -ion (from Latin -io) is fixed to a base or to another suffix ending in -t or -te. In Middle English, in words via Old French, it often was -cion (in coercion and suspicion, however, the -c- belongs to the base).