reciprocal in WordNet English dictionary

1. (mathematics) one of a pair of numbers whose product is 1: the reciprocal of 2/3 is 3/2; the multiplicative inverse of 7 is 1/7
   multiplicative inverse  reciprocal 
   
2. hybridization involving a pair of crosses that reverse the sexes associated with each genotype
   reciprocal cross  reciprocal 
   
3. something (a term or expression or concept) that has a reciprocal relation to something else
   "risk is the reciprocal of safety"
   reciprocal 
   

1. concerning each of two or more persons or things; especially given or done in return
   "reciprocal aid"; "reciprocal trade"; "mutual respect"; "reciprocal privileges at other clubs"
   reciprocal  mutual 
   
2. of or relating to the multiplicative inverse of a quantity or function
   "the reciprocal ratio of a:b is b:a"
   reciprocal