the GNU version of the Collaborative International Dictionary of English
n. The quality or condition of being reciprocal; mutual return; alternateness.
The Century Dictionary and Cyclopedia
n. The state or character of being reciprocal.
Word Usage
"These differences are — as an expression of that manifoldness of being which is necessary to the perfection of the whole — per se good, and give rise to a vital reciprocalness of relation among the members of society."