Vaisesika Sūtra 5.2.16

तदनारम्भ आत्मस्थे मनसि शरीरस्य दुःखाभावः सः योगः ॥१६॥

tadanārambha ātmasthē manasi śarīrasya duḥkhābhāvaḥ saḥ yōgaḥ ॥16॥

[तत्-अनारम्भे (tat-anārambhe) - when that is not initiated; आत्म-स्थे-मनसि (ātma-sthe-manasi) - in the mind fixed in ātman; शरीरस्य-दुःख-अभावः (śarīrasya-duḥkha-abhāvaḥ) - absence of body’s pain; सः-योगः (saḥ-yogaḥ) - that is yoga;]

When not initiated, and the mind is fixed in the ātman, the body’s pain is absent — that is Yoga.