push-pull

Short definition from Wiktionary

Adjective

1. 1
   Operated by pushing and pulling.
2. 2
   Operated by pushing and pulling: Operating with locomotives at both the head and rear of a train, or with a locomotive at one end and a driving position in the vehicle at the opposite end, so that the train can be driven from either end.
3. 3
   Having two electronic devices in opposite phase.

Noun

1. 1
   An alternation or fluctuation between two opposites; a back-and-forth dispute, a tug of war.