The anomalously formed word ṣaṣṭikāḥ has the meaning of 'what are matured in six nights'.,
The word षष्टिकाः may be said to be formed by adding कन् to षष्टिरात्रि in the 3rd case in construction, then eliding the word रात्रि, the force of the affix being 'matured'. Thus षष्टिरात्रेण पच्यन्ते = षष्टिकाः 'a kind of barley'. It is a name of barley and therefore does not apply to pulse, beans &c, though they may also ripen in six days.,