noun-modifying (irregular)
Technical term used as a prenominal modifier in engineering contexts, especially for mechanisms that respond to differences in motion, pressure, or other quantities.
差動装置は車の旋回をスムーズにする。
The differential device makes the car's turning smoother.
このロボットは差動駆動方式を採用している。
This robot uses a differential drive system.
Compound of 差 (difference) and 動 (motion), literally 'difference motion'. The exact historical derivation is uncertain, but the term is used in modern technical vocabulary.