noun, noun or participle which takes 'suru', intransitive verb
General term for a response to an action, statement, or event. Covers emotional, verbal, and behavioral reactions.
彼の冗談に誰も反応しなかった。
No one reacted to his joke.
そのニュースに対する国
The public's reaction to the news was mixed.
noun, noun or participle which takes 'suru', intransitive verb
physical response; physiological reaction
Used for observable biological or physical responses to stimuli, such as reflexes, sensory reactions, or organism-level responses.
瞳孔は光に反応して小さくなる。
The pupil contracts in response to light.
この薬に対する体の反応を調べています。
We are investigating the body's reaction to this drug.
noun, noun or participle which takes 'suru', intransitive verb
chemical reaction
Technical term in chemistry for a process where substances interact and change. Often used in compounds like 化学反応 (chemical reaction).
鉄が酸素と反応して錆びる。
Iron reacts with oxygen and rusts.
この化学反応では熱が発生する。
This chemical reaction produces heat.