After the words expressive of time, the affixes denoting 'who stays there' -- kālāṭṭhañ [[4.3.11]] to tatra bhavaḥ [[4.3.53]], come also in the sense of 'this its deity'.,
Thus by 4.3.11 (read with 4.3.53), the affix ठञ् comes after the words expressive of time, in the sense of 'who stays there'. The same affix will also come in the sense of साऽस्यदेवता ॥ Thus मासे भवं = मासिकम् (मास + ठञ् = मास = इक 7.3.50); अर्द्धमासिकम्, सांवत्सरिकम्, वासन्तम् 4.3.16, प्रावृषेण्यम् 4.3.17 : meaning 'monthly', 'half monthly', 'annual', 'vernal', and 'rainy'. The words will also mean 'an oblation sacred to a month i.e' as मासो देवताऽस्य मासिकम् ॥ &c.,