cetasika: 'mental things, mental factors', are those mental concomitants which are bound up with the simultaneously arising consciousness (citta = viññāṇa) and conditioned by its presence . Whereas in the Suttas all phenomena of existence are summed up under the aspect of 5 groups: corporeality, feeling, perception, mental formations, consciousness (s. khandha), the Abhidhamma as a rule treats them under the more philosophical 3 aspects: consciousness, mental factors and corporeality (citta, cetasika, rūpa). Thus, of these 3 aspects, the mental factors (cetasika) comprise feeling, perception and the 50 mental formations, altogether 52 mental concomitants. Of these, 25 are lofty qualities (either kammically wholesome or neutral), 14 kammically unwholesome, while 13 are as such kammically neutral, their kammical quality depending on whether they are associated with wholesome, unwholesome or neutral consciousness. For details s. Tab. II, III. Cf. prec. (App . )

Buddhist Dictionary, Manual of Buddhist Terms and Doctrines, by NYANATILOKA MAHATHERA

cetasika

(Pāli; Skt., caitasika). An early Abhidharma term denoting psychological phenomena of various kinds that arise in the mind (citta) as it encounters and processes phenomena. There are 52 according to Theravādin sources. In Buddhist scholastic psychology the theory of cetasikas is the outcome of the attempt to classify and describe in detail the different states of mind and their various functions in the context of a general account of the modal operations of the psyche (citta). The endeavour is an outgrowth of the canonical classification of the human subject into five categories or ‘aggregates’ (skandha) and aims at greater precision in the tabulation of mental elements and faculties in each of the five categories. The different schools tabulate the psychic qualities differently, but all tend to follow a general breakdown into three categories: (1) general psychological functions, e.g cognition or discrimination (saññā), sensation or feeling (vedanā), volition (cetanā), discursive thought (vicāra), focused concentration (ekaggatā), etc. (2) Wholesome or virtuous qualities, e.g. goodwill (adosa), non-attachment (alobha), diligence (appamāda), confidence (saddhā), etc. (3) Unwholesome qualities or vices, e.g. hatred (dosa, Skt. dveṣa), envy (issā), conceit (māna), etc. In Sanskrit sources the cetasikas are known as caittas, and the classification varies slightly.

A Dictionary of Buddhism, Oxford University Press, 2003, 2004 (which is available in electronic version from answer.com)

cetasika : [adj.] mental; (nt.), a mental property.

A.P. Buddhadatta Mahathera, Concise Pali-English and English-Pali Dictionary [available as digital version from Metta Net, Sri Lanka]

Cetasika (adj.) belonging to ceto, mental (opp. kāyika physical). Kāyikaŋ sukhaŋ > cetasikaŋ s. A i.81; S v. 209; kāyikā darathā > c. d. M iii.287, 288; c. duk khaŋ D ii 306; A i.157; c. roga J iii.337. c. kamma is sīla 8 -- 10 (see under cetanā) Nett 43. -- As n. combd with citta it is to be taken as supplementing it, viz. mind & all that belongs to it, mind and mental properties, adjuncts, co -- efficients (cp. vitakka -- vicāra & sach cpds. as phalâphala, bhavâbhava) D i.213; see also citta. Occurring in the Nikāyas in sg. only, it came to be used in pl. and, as an ultimate category, the 52 cetasikas, with citta as bare consciousness, practically superseded in mental analysis, the 5 khandha -- category. See Cpd. p. 1 and pt. II. Mrs. Rh. D., Bud. Psy. 6, 148, 175. -- ˚cetasikā dhammā Ps i.84; Vbh 421; Dhs 3, 18, etc. (cp. Dhs. trsl. pp. 6, 148).

Pali-English Dictionary, TW Rhys Davids, William Stede,