tasyaiva cānte kalpo ’bhūd
yaṁ pādmam abhicakṣate
yad dharer nābhi-sarasa
tasya—of the Brāhma-kalpa; eva—certainly; ca—also; ante—at the end of; kalpaḥ—millennium; abhūt—came into existence; yam—which; pādmam—Pādma; abhicakṣate—is called; yat—in which; hareḥ—of the Personality of Godhead; nābhi—in the navel; sarasaḥ—from the reservoir of water; āsīt—there was; loka—of the universe; saroruham—lotus.
The millennium which followed the first Brāhma millennium is known as the Pādma-kalpa because in that millennium the universal lotus flower grew out of the navel reservoir of water of the Personality of Godhead, Hari.
The millennium following the Brāhma-kalpa is known as the Pādma-kalpa because the universal lotus grows in that millennium. The Pādma-kalpa is also called the Pitṛ-kalpa in certain Purāṇas.
Link to this page: https://prabhupadabooks.com/sb/3/11/36