Words ending in -sion, -tion, and -cion

These endings are part of many everyday English nouns but people often have problems with their spelling. Here are some guidelines to help you choose the right one:

Words ending in -sion

  • If the ending is pronounced as in confusion, then it should be spelled -sion. Here are some examples:

collision; division; revision; persuasion; explosion; decision; seclusion.

  • When the ending comes after an -l, it's always spelled -sion:

compulsion; revulsion; expulsion; emulsion; propulsion.

  • When the ending follows an -n or -r, it's often spelled -sion, especially if the word is related to one that ends in -d or -se. For example: immersion (from immerse); comprehension (from comprehend). Here are some more examples:

aversion; conversion; apprehension; diversion; extension; version.

commission; expression; aggression; admission; succession; impression; emission.

Words ending in -tion

  • If the ending is pronounced as in station, then it's spelled -tion. For example:

addition; duration; nation; solution; ambition; edition; caution; position.

  • If the noun is related to a word ending in -ate, then the ending will be -ation, e.g. donation (from donate) or vacation (from vacate). Here are some more examples:

accommodation; location; creation; rotation; education; mediation.

  • If the ending comes after any consonant apart from -l, -n, or -r, then the ending is spelled -tion:

action; connection; reception; affection; interruption; description; collection; infection; deception.

  • After -n and -r, the ending can be -tion or -sion. It's more likely to be -tion if the word's related to another one that ends in -t or -tain, e.g. assertion (from assert) or retention (from retain). Here are some more examples:

exertion; distortion; abstention; invention.

Words ending in -cion

There are just two common nouns that end in -cion: suspicion and coercion.

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Grammar and usage