1. Concerning each of two or more persons or things. 2. reciprocal agreements to abolish customs duties; a reciprocal invitation to lunch. 3. reciprocal respect. 4. reciprocal electric outlets. 5. Expressing mutual action or relationship. Used of some verbs and compound pronouns. 6. Of or relating to the reciprocal of a quantity. 7. Of or relating to a neuromuscular phenomenon in which the excitation of one group of muscles is accompanied by the inhibition of another. 8. Of or designating a pair of crosses in which the male parent in one cross is of the same genotype or phenotype as the female parent in the other cross. 9. Something that is reciprocal to something else. 10. .
