The affix kha optionally in the senses taught in tena nirvṛttam [[5.1.79]], dvigoryap [[5.1.82]], after the words 1. rātrī 2. ahan and 3. samvatsara , occasioning a dvigu samāsa (Numeral Determinative Compound).,
In the alternative ठञ् will also come. Thus द्विरात्रीणः, द्वैरात्रिकः, द्व्यहीनः 6.4.145 or द्वैयह्निकः, द्विसंवत्सरीणः, द्विसांवत्सरिकः 7.3.15.,