aṣṭa-vimokṣāḥ [aṭṭha-vimokkhā] eight meditations for emancipation.

Vimokṣa means emancipation. There are eight kinds of meditation practised to attain eight types of emancipation. These are(1) to meditate on the impurity of one's own body for the sake of removing passions,
(2) to meditate on the impurity of external objects in order to strengthen emancipation from passions,
(3) to meditate on the purity of external objects in order to overcome passions,
(4) to meditate on the boundless consciousness in order to overcome the attachment to corporeality-perceptions. Through this meditation one reaches the sphere of the unbound space and abides therein.
(5) to meditate on the boundless consciousness in order to remove attachment to void. Through this meditation one reaches the sphere of the unbounded consciousness and abides therein.
(6) to meditate on the non-existence in order to remove attachment to consciousness. Through this meditation one reaches the sphere of nothingness and abides therein.
(7) to meditate on the state of neither thought nor non-thought in order to remove attachment to non-existence. Through this meditation one reaches the sphere of neither perception nor non-perception and abides therein.
(8) putting an end to all thoughts and perceptions and dwelling in the state of total extinction. By doing so one reaches the extinction of perception and thoughts.

Buddhānusmṛti - A Glossary of Buddhist Terms

Aṭṭhasālinī. I. 301-303. Aṅguttara Nikāya. Vimokkha. Dīgha Nikāya. Mahānidāna, Poṭṭhapāda, Saṅgīti. Majjhima Nikāya. Saḷāyatana. Mahāyāna-Sūtrālaṅkāra. XVIII.