CC Madhya 24.20
caraṇa-cālane kāṅpāila tribhuvana
“ ‘Krama’ also means ‘power,’ ‘trembling,’ ‘a systematic method,’ ‘argument’ and ‘a forcible attack by stepping forward.’ Thus Vāmana caused the three worlds to tremble.
Uru means “very great,” and krama means “step.” When Lord Vāmanadeva was offered three steps of land, He expanded His three steps by covering the entire universe. In this way the three worlds trembled, and therefore Śrī Vāmanadeva, the incarnation of Lord Viṣṇu, is referred to as Urukrama.