reciprocal
adjective
°Of an action, feeling, etc, done, felt, etc, by each of two people to, on or towards the other.
°In the contrary or opposite way, order, or direction.
noun
°Of a number, the number obtained by dividing 1 by the given number; the result of exchanging the numerator and the denominator of a fraction.
synonyms: mutual, two-way, converse, inverse more» , inverted, cross, multiplicative, inverse