hetú m. ‘impulse’, motive, cause, cause of, reason for (loc., rarely dat. or gen.; hetunā, hetoḥ, hetave, hetau, ‘for a cause or reason’, ‘by reason of’, ‘on account of’ [with gen. or comp., e.g. mama hetoḥ or mad-dhetoḥ, ‘on account of me’]; kaṃ hetum or ko hetuḥ, ‘wherefore?’ ‘why?’, [Pāṇ. ii, 2, 23]; [Pat.]; yato hetoḥ, ‘because’; anena hetunā or iti hetoḥ, ‘for this reason’; mṛtyu-hetave, ‘in order to kill’; hetur alaukikaḥ, ‘a supernatural cause’; ifc. also = ‘having as a cause or motive’, ‘caused or effected or actuated or attracted or impelled by’ e.g. karma-hetu, ‘caused by the acts [of a former existence]’, [Mn. i, 49]; māṃsa-hetu, ‘attracted by [the smell of] flesh’, [MBh. x, 496]; karma-phala-hetu, ‘impelled by [the expectation of] the consequences of any act’, [BhP. ii, 47]; [49]), [RV.] &c. &c.
a logical reason or deduction or argument, the reason for an inference (esp. applied to the second member or Avayava of the five-membered syllogism See nyāya), [Nyāyad.]; [IW. 61]
logic (in general See hetuvidyā)
(in gram.) the agent of the causal verb, [Pāṇ. i, 4, 55] &c.
(with Buddhists) primary cause (as opp. to pratyaya, q.v.), [Sarvad.]
(with Paśu-patis) that which causes the bondage of the soul i.e. the external world and the senses, [ib.]