parihāṇa [parihāna] loss. The Sanskrit root hā means to give up, parihāṇa means giving up, that is, loss. An aspirant who has reached absorptions of the realm of form or the formless realms should be wakeful; otherwise he may fall from the absorption. If the process of reaching the absorption is not natural, if the place and time do not suit the aspirant or if he has attained the absorption with a lot of painstaking effort, he might lose the state. The loss is called parihāṇa.  

Buddhānusmṛti - A Glossary of Buddhist Terms

Dīgha Nikāya. Saṅgīti. Mahāyāna-Sūtrālaṅkāra. XVI. 108; XIX. 158.