The fifth stage of Dhāraṇā (retention); in which the retained knowledge is made firmly secured i.e., it does not get obliterated.
kotthe ttijahā kotthage sālimādibhjāpakkhitta avinatthā dhārijjamti tahā avātāvaāhāritamattham gurūvadittham suttamattham vā avinattham dhārayato dhāranā kotthagasama tti kātum kotthe tti vattavvā.
(Nandī 49 Cū p. 37)