samatha: 'tranquillity', serenity, is a synonym of samādhi (coneentration), cittekaggatā (one-pointedness of mind) and avikkhepa (undistractedness). It is one of the mental factors in 'wholesome consciousness. Cf. foll. and bhāvanā.
śamatha
(Sanskrit; Pāli, samatha; calming). One of the two main types of meditational technique taught in Buddhism, the other being vipaśyanā or insight meditation. It is normally recommended that the two techniques be developed in tandem since they complement one another. The primary aim of śamatha is to achieve the state of mental absorption known as ‘one-pointedness of mind’ (citta-ekāgratā), in which state the mind remains focused unwaveringly on its meditation subject. When the mind is calm and focused in this way it can successively attain the eight dhyānas (Pāli, jhānas) or trances. By contrast, vipaśyanā meditation leads to the intellectual understanding of doctrine and depends upon the mind being in a state of conscious awareness. The primary technique used in śamatha is to concentrate on the breath as it enters and leaves the body, perhaps counting the in and out breaths up to a certain number and then resuming again at zero. The aim is to monitor the breath with bare attention rather than trying to control it. Other methods include focusing on an external object, known in Pāli sources as a kasiṇa, or by concentrating on any of the 40 traditional meditation subjects. These practices lead to physiological changes in the body and an altered state of consciousness which is amenable to spiritual development. The practice of śamatha frees the mind from distractions and removes mental impurities such as the five hindrances (nīvaraṇa), which are left behind on the attainment of the first dhyāna.
śamatha: Calm, tranquility. As a meditation practice, it is distinct from (though not opposed to) vipaśyanā.