The rate of a reaction at a particular moment, rather than an average rate over a period of time.

प्रतिक्रिया की किसी विशेष क्षण पर दर, न कि एक अवधि के औसत दर।

English Usage: The scientist measured the instantaneous rate of reaction during the experiment.

Hindi Usage: वैज्ञानिक ने प्रयोग के दौरान तात्कालिक प्रतिक्रिया दर को मापा।