1. (n.) The act of reciprocating; interchange of acts; a mutual giving and returning; as, the reciprocation of kindnesses.

2. (n.) Alternate recurrence or action; as, the reciprocation of the sea in the flow and ebb of tides.

Lissajous figure alternation back-and-forth balance battledore and shuttlecock boomerang coequality comeback coming and going communion community commutation cooperation corelation correlation correlativism correlativity correspondence counter counterblast counterblow counterchange counterstroke cross fire ebb and flow equilibrium equipollence equivalence exchange flux and reflux give-and-take interchange intermutation interplay inverse proportion inverse ratio inverse relationship lex talionis measure for measure mutual admiration mutual support mutual transfer mutuality permutation proportionality quid pro quo reciprocality reciprocity recoil relativity reply retaliation retort return rhythmic play seesaw seesawing sine wave something for something symmetry teeter teeter-totter teeter-tottering teetering tit for tat to-and-fro tottering transposal transposition ups and downs wigwag