416
Śrīmad-Bhāgavatam
[ Canto 3, Ch. 11 ]
tayoḥ samuccayo māsaḥ pitṛṇām tad aharniśam dvau tāv ṛtuḥ ṣaḍ ayanam dakṣiṇam cottaram divi
tayoḥ —of them;  samuccayaḥ —aggregate;  māsaḥ —month;  pitṛṇām —of the Pitā planets;  tat —that (month);  ahaḥ-niśam —day and night;  dvau —two;  tau —months;  ṛtuḥ —a season;  ṣaṭ —six;  ayanam —movement of the sun in six months;  dakṣiṇam —southern;  ca —also;  uttaram —northern;  divi —in the heavens.
TRANSLATION
The aggregate of two fortnights is one month, and that period is one complete day and night for the Pitā planets. Two of such months comprise one season, and six months comprise one complete movement of the sun from south to north.
TEXT 12
अयने चाहनी प्रादुर्वत्सरो द्वादश स्मृतः । संवत्सरशतं नृणां परमायुर्निरूपितम् ॥१२॥
ayane cāhanī prāhur vatsaro dvādaśa smṛtaḥ saṁvatsara-śatam nṛṇām paramāyur nirūpitam
ayane —in the solar movement (of six months);  ca —and;  ahanī —a day of the demigods;  prāhuḥ —it is said;  vatsaraḥ —one calendar year;  dvādaśa —twelve months;  smṛtaḥ —is so called;  saṁvatsara-śatam —one hundred years;  nṛṇām —of human beings;  parama-āyuḥ —duration of life;  nirūpitam —is estimated.
TRANSLATION
Two solar movements make one day and night of the demigods, and that combination of day and night is one complete calendar year for the human being. The human being has a duration of life of one hundred years.