reciprocal
adjective formal uk/rɪˈsɪp.rə.kəl/ us/rɪˈsɪp.rə.kəl/
相互的;互惠的;报答的
A reciprocal action or arrangement involves two people or groups of people who behave in the same way or agree to help each other and give each other advantages.
reciprocal
noun [ C ] uk/rɪˈsɪp.rə.kəl/ us/rɪˈsɪp.rə.kəl/
（数学）倒数
a number that, when multiplied by another number, results in 1