From Zenwiki

Prajñā (prognosis, 音訳:般若、和訳:恵、慧、知恵、智慧) is pra-jñā (pro-gnosis, forward-knowledge, far/wide/deep insight, how-to-knowledge). This is attained by witnessing nirvana (nir-vāņa or ni-vāta, no-wind, of karma, cf. nivāte padīpa, in-windlessness lamp/candle flame). In nirvana one can witness suñña, śūnya, Arabic zifr/sifr, European zero/empty (of eternal/independent entity/substance) due to the Dharma of Dependent Co-origination (of physical/mental phenomena, see 12-fold/limbed Dependent Co-origination).