Vaisesika Sūtra 1.1.20

संयोगविभागवेगानां कर्म समानम् ॥२०॥

saṁyoga-vibhāga-vegānāṁ karma sāmānam ॥20॥

[संयोग-विभाग-वेगानाम् (saṁyoga-vibhāga-vegānām) - of conjunction, disjunction, and motion; कर्म (karma) - action; समानम् (sāmānam) - is common;]

Movement is the generality of the speed of combination and disjunction.