A relationship in which two things correspond to each other.

In mathematics or physics, it can refer to a quantity that is the inverse of another quantity.

प्रतिकूल

English Usage: The reciprocal of a fraction is obtained by flipping the fraction upside down.

Hindi Usage: एक भिन्न का प्रतिकूल उसे पलटकर प्राप्त किया जाता है।