Which suffix indicates 'process'?

• A. -ion
• B. -osis
• C. -ism
• D. -ory

Answer: (A)

Suffixes that name an action or the act of doing something express a process. The suffix -ion forms nouns from verbs that denote the action or process itself, making it the natural way to express “the process of X.” For example, digestion is the process of digesting; inhalation is the process of inhaling; circulation is the process of circulating. That direct sense of “the action or activity” is what ties -ion to a process.

The other endings point to different ideas. -osis usually marks a condition or disease state, not the action itself. -ism refers to a belief, doctrine, or system, or sometimes a characteristic, rather than the ongoing process. -ory typically means pertaining to or a place for something, and it often forms adjectives or nouns related to function rather than the process itself.

So -ion best signals the concept of a process.