Vaisesika Sūtra 5.2.06

नोदनपीडनात् संयुक्तसंयोगाच्च ॥६॥

nōdanapīḍanāt saṁyuktasaṁyōgāc ca ॥6॥

[नोदन-पीडनात् (nodana-pīḍanāt) - from impelling pressure; संयुक्त-सम्योगात्-च (saṁyukta-saṁyogāt-ca) - and from compound conjunction;]

It arises from impelling pressure and compound conjunction.