alternation (n.)
- beat
- chain
- coaction
- commutation
- concurrence
- cooperation
- engagement
- exchange
- fluctuation
- give-and-take
- interaction
- interchange
- intercommunication
- intercourse
- intermittence
- intermittency
- interplay
- mesh
- meshing
- meter
- mutuality
- order
- oscillation
- periodicity
- permutation
- progression
- pulsation
- reappearance
- reciprocality
- reciprocation
- reciprocity
- recurrence
- repetition
- retaliation
- return
- reversion
- rhythm
- rotation
- row
- seesaw
- sequel
- sequence
- series
- shifting
- shuffling
- succession
- teeter
- teeter-totter
- train
- transposition
- undulation
- vacillation
- variation
- vicissitude
- wavering
