reciprocation (n.)

• alternation
• balance
• boomerang
• comeback
• communion
• community
• commutation
• cooperation
• correlation
• correlativity
• correspondence
• counter
• counterblast
• counterblow
• equilibrium
• equivalence
• exchange
• give-and-take
• interchange
• interplay
• mutuality
• permutation
• proportionality
• reciprocality
• reciprocity
• recoil
• relativity
• reply
• retaliation
• retort
• return
• seesaw
• symmetry
• teeter
• teeter-totter
• transposition