Vedanā: 'feeling', sensation, is the 2nd of the 5 groups of existence see: khandha. According to its nature, it may be divided into 5 classes: 1 bodily pleasant feeling kāyikā sukhā-vedanā = sukha 2 bodily painful feeling kāyikā dukkhā-vedanā = dukkhā 3 mentally pleasant feeling cetasikā sukhā-vedanā = somanassa 4 mentally painful feeling cetasikā dukkhā-vedanā = domanassa 5 indifferent or neutral adukkha-m-asukhā vedanā = upekkha.
With regard to the 6 senses, one distinguishes 6 kinds of feeling: feeling associated with seeing, hearing, smelling, tasting, bodily contact and mental contact. The textual wording of it is 'feeling arisen through visual contact' cakkhu-samphassajā vedanā a href=dic2-abbrev.htm#S. see: XXII, 55; D. 22, etc.
Feeling is one of the 7 mental properties inseparably associated with all consciousness whatever, see: nāma In the formula of the dependent origination paticcasamuppāda, feeling is the condition for the arising of craving tanhā The above-mentioned 5 kinds of feeling are enumerated amongst the 22 abilities indriya. - See M. 59; Contemplation of Feeling Vedanā Samyutta, by Nyanaponika Thera WHEEL 303/304.
Maha Thera Nyanatiloka. Manual of Buddhist Terms and Doctrines, Buddhist Publication Society, first edition 1952.