Right view in the noble eightfold path is knowledge (ñāṇa) of suffering (dukkha), knowledge of the arising of suffering, knowledge of the ceasing of suffering, and knowledge of way leading to the ceasing of suffering.
It also in the Saṃyutta-nikāya/Saṃyukta-āgama refers to fully knowing (jānāti) and seeing (passati) phenomena (the five aggregates/sense objects) as:
(1) impermanent (anicca), suffering (dukkha), not-self (anatta) (or anicca, dukkha, suñña (empty), anatta)
and
(2) the middle way (P. majjhima-paṭipadā, Skt. madhyama-pratipad).
The middle way is empty of two extremes: existence (eternalism) and non-existence (nihilism), or the happiness of sense-pleasures and the suffering of self-mortification.