Viveka: 'isolation', seclusion, is according to Niddesa, of 3 kinds: 1 bodily detachment kaya-viveka i.e. abiding in solitude free from alluring sense-objects; 2 mental detachment citta-viveka i.e. the inner detachment from sense-things; 3 detachment from the substrata of existence upadhi-viveka.
Maha Thera Nyanatiloka. Manual of Buddhist Terms and Doctrines, Buddhist Publication Society, first edition 1952.