Reciprocation /(rē̇*sĭp"rō̇*kā"shŭn)/

Re·cip·ro·ca·tion

Reciprocation

n.
  1. The act of reciprocating; interchange of acts; a mutual giving and returning; as, the reciprocation of kindness.
  2. Alternate recurrence or action; as, the reciprocation of the sea in the flow and ebb of tides.