Vyavahāra

vyavahāra. (T. tha snyad; C. sudi/yanyu; J. zokutai/gongo; K. sokche/ŏnŏ 俗諦/言語). Translated as: conventional designation; ordinary convention; worldly convention; established convention; term, name, word; etc.

The Princeton Dictionary states:

Vyavahāra has two general applications in a Buddhist context. First, it is used to indicate the established social conventions, experiences, and practices of the quotidian world. In Buddhism, these conventions are contrasted with the strict moral practices that conform to the ultimate truth (paramārthasatya) perceived by noble beings (ārya). In this sense of a “conventional truth,” vyavahārasatya is synonymous with saṃvṛtisatya.

Second, and rather more commonly, this term is used in the context of language and discourse to indicate those conventional words used by ordinary, unenlightened beings to designate reality as they (mis)understand it. Here, again, the terms and the objects that they designate are merely conventional truths (saṃvṛtisatya); the term vyavahārasatya sometimes is used as a synonym. Since, according to the doctrine of emptiness (śūnyatā), all phenomena are devoid of any inherent, unchanging nature, the linguistic expressions used to designate the things of this world are purely conventional designations and cannot contain or communicate the true nature of those phenomena.

Sources

• Buswell, Robert E.; Lopez, Donald S. (2014), The Princeton Dictionary of Buddhism, Princeton University 
• Pettit, John Whitney (1999), Mipham's Beacon of Certainty: Illuminating the View of Dzogchen, the Great Perfection, Wisdom Publications