Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 6 · Calendar, Muhurta Elements
कालमानं मुहूर्ताङ्गानि च
मधुश्च माधवः शुक्रः शुचिश्चाथ नभस्ततः ।नभस्य इष ऊर्जश्च सहाश्चैव सहस्यकः ॥ १३० ॥
In the full Narada Purana (Purva Bhaga) this is chapter 56, verse 130.
Madhu, Madhava, Shukra, Shuchi, then Nabhas, Nabhasya, Isha, Urja, Saha and Sahasya.
Simple meaning: These are the first ten names of the twelve lunar months.
तपास्तपस्य क्रमशश्चैत्रादीनां समाह्वयाः ।
Tapas and Tapasya are the last two month names. The rest of the sentence runs into the next verse.
तन्नक्षत्राह्वयो मासः पौर्णमासी तदाह्वया ।
A month is named after the star its full moon sits in. Its two fortnights are the bright and the dark.
शुभाशुभे कर्मणि च प्रशस्तौ भवतः सदा ।
The two fortnights are both praised for acts. The first five moon days are ruled by Brahma, Agni, Virinchi, Vishnu and Shailaja.