No difference. Vamana is the avatar of Lord Vishnu who incarnated to bestow upon King Mahabali (grandson of Prahlad) the title of Lord of Sutala and a boon to become the Indra of the yet to come Savarni Manu. He blessed Mahabali with his third step on his head. Tri means three, krama means step or stride. So Trivikrama means, "he who takes three strides" to cover all of creation. See picture blow for Vamana becoming Trivikrama.
No difference. Vamana is the avatar of Lord Vishnu who incarnated to bestow upon King Mahabali (grandson of Prahlad) the title of Lord of Sutala and a boon to become the Indra of the yet to come Savarni Manu. He blessed Mahabali with his third step on his head. Tri means three, krama means step or stride. So Trivikrama means, "he who takes three strides" to cover all of creation. See picture blow for Vamana becoming Trivikrama.