Hi inflib,
The following are the consciousness of the arupavacara (immaterial plane or formless plane) where the jhana are attained:
ākāsānañcāyatana means sphere of infinite space
viññāṇañcāyatana means sphere of infinity of consciousness
ākiñcaññāyatana means sphere of nothingness
nevasaññānāsaññāyatana means sphere of neither perception nor non perception
See bottom for the meaning of āyatana.
In the sutta definition, the following jhana applies:
5th jhana is ākāsānañcāyatana
6th jhana is viññāṇañcāyatana
7th jhana is ākiñcaññāyatana
8th jhana is nevasaññānāsaññāyatana
The 7th jhana is where the bodhisatta Siddhartha attained under Alara Kalama guidance and the 8th jhana is achieved under Uddaka Ramaputta during his search for Enlightenment.
With metta Seng Kiat
āyatana：1．’spheres’，is a name for the four immaterial absorptions; s．jhāna （5-8）．2．The 12 ‘bases’ or ‘sources’ on which depend the mental processes，consist of five physical sense-organs and consciousness，being the six personal （ajjhattika） bases; and the six objects，the so-called external （bāhira） bases – namely：
eye，or visual organ visible object
ear，or auditory organ sound，or audible object
nose，or olfactory organ odour，or olfactive object
tongue，or gustatory organ taste，or gustative object
body，or tactile organ body-impression，or tactile object
mind-base，or consciousness mind-object