The -tion / -sion Suffix: Turning Verbs into Nouns

One of the most productive patterns in English vocabulary is quiet and easy to miss once you already know the words: a huge number of nouns are just verbs wearing a -tion or -sion ending. Once you notice the pattern, it turns a lot of unfamiliar nouns into words you can half-guess on sight.

What the suffix actually does

Adding -tion or -sion to a verb (sometimes with a small spelling adjustment) creates the noun form of that same action or its result. Decide becomes decision, the noun naming the act or result of deciding. Abolish becomes abolition, the noun for the act of abolishing something. Absorb becomes absorption, following the same logic with a slightly less obvious spelling shift.

Why the spelling isn't always obvious

Whether a word takes -tion or -sion, and how much the base verb changes shape in the process, isn't fully predictable from the verb alone. "Decide" drops the final -e and takes -sion; "abolish" drops -ish and takes -tion. There's no shortcut that avoids just learning each pair, but recognizing that a pair exists at all is most of the battle.

Why this pattern is worth learning deliberately

Once you know a verb, spotting its noun form usually isn't a new vocabulary item so much as a small transformation of something you already know. That means a relatively modest number of verb/noun pairs, learned as pairs rather than in isolation, effectively doubles your usable vocabulary for a fraction of the effort of learning two unrelated words.

Where this shows up most

Academic and exam vocabulary leans on -tion/-sion nouns constantly, since formal writing favors nouns ("the decision was made") over the more conversational verb form ("they decided"). Our IELTS vocabulary guide and our TOEFL vocabulary guide both cover why this noun-heavy register matters specifically for academic exams.

Recognizing the pattern on a page is one thing. Producing the right noun form on demand, mid-sentence, is a different and harder skill. A quiz tests the second one.