Yāska's Nirukta 19.3.2

19.3.2

adhunaivamuktvodāharaṇaireva tatra sandehapadānyanukramya mantreṣveva darśayannāha,–“imānyekaviṃśatiḥ pṛthivīnāmadheyānyanukrāntāni tatra nirṛtirniramaṇādṛcchateḥ kṛcchrāpattiritarā” | lokeṣu hīdaṃ sarvaṃ bhūtajātamantarbhūtam, yadabhidhānāni yadāśrayakriyāvacanāśca śabdā nighaṇṭava ucyante, teṣāṃ ca pṛthivī prathamā, tasmāt tata ārambhaḥ | ekaviṃśatiriti saṃkhyā 21 | pṛthivīnāmadheyāni, svārthe dheyapratyayaḥ, nāmaiva nāmadheyam | anukrāntāni, ānupūrvyeṇa paṭhitānītyarthaḥ | ekaviṃśatiryānyanukrāntāni, ebhyo'nyānyapi yāni kānicit syuḥ, tānyupalabhya nirvaktavyāni | tadyathā,ku ityetadasamāmnātaṃ pṛthivyā nāmadheyam | uktaṃ hi - ‘nābhicinnarakaṃ yāti na satputro na kupradaḥ'--iti || tatraitasminnekaviṃśake nāmagaṇe nirṛtiḥ ityetadabhidhānam | niramaṇāt niviṣṭāni ramante'syāṃ bhūtānīti nirṛtiḥ pṛthivī | ramerdhātoḥ ( bhū0 ā0 ) | ṛcchateḥ (tu0pa0 ) itarā kṛcchrāpattiḥ duḥkhasañjñikā, nirṛtiḥ pāpmā | “sā” punariyaṃ samānanāmadheyatvāt samānaśrutitvāt “pṛthivyā sandihyate” | “tayoḥ” samānanāmadheyatve'pi sati eṣa karmakṛto “vibhāgaḥ”–ekā niviṣṭānāṃ bhūtānāṃ ramayitrī, ekā punaḥ kṛcchramāpādayitrī | evaṃ nānākarmāṇyabhidhānāni nirvaktavyāni | 7 | "tasyāḥ" kṛcchrāpatteḥ pṛthivyā api “eṣā” nirvrācikā ṛg “bhavati-”