(karmic) 'accumulation', is a name used in the commentarial literature for the wholesome and unwholesome volitional activities (karma, q.v.) or karma-formations (sankhāra; s. paticca-samuppāda), being the bases of future rebirth.
'Accumulation', is a name for the karma-formations, and signifies those volitions (cetanā) which arise at the performance of a karma, first while thinking 'I will give alms', and then while actually giving alms (e.g.) for one month or a year.
The volition, however, at the time when one is handing the alms over to the recipient; is called karma-process (kamma-bhava, s. Vis.M. XVII, IX, X).
Or, the volitions during the first six impulsive-moments (javana, q.v.) depending on one and the same state of advertence (āvajjana, s. viññāna-kicca), these are called the karma-formations, whilst the 7th impulsive moment is called the karma-process (kamma-bhava)....
Or, each volition is called 'karma-process' and the accumulation connected with it, 'karma-formation'. " (Vis.M. XVII). Cf. paticca-samuppāda (2, 10) - (App.).