a response to an event or situation

a chemical change resulting from a specific stimulus

प्रतिक्रिया

English Usage: Her reaction to the news was unexpected.

Hindi Usage: खबर पर उसकी प्रतिक्रिया अप्रत्याशित थी।

an emotional response

भावनात्मक प्रतिक्रिया

English Usage: His reaction was filled with joy when he saw her.

Hindi Usage: जब उसने उसे देखा, तो उसकी प्रतिक्रिया खुशी से भरी हुई थी।

to respond to something

प्रतिक्रिया देना

English Usage: You need to react quickly in emergencies.

Hindi Usage: आपात परिस्थितियों में आपको जल्दी प्रतिक्रिया देनी चाहिए।