When a pollen from a flower falls on the stigma of another flower in another plant of the same species, it is called
Cross-pollination
Cross-pollination is a type of pollination in which the transfer of pollen from the anther of one flower to the stigma of another flower on a different plant of the same species. On the other hand, when the pollen from the anther is deposited on the stigma of the same or another flower on the same plant, it is known as self-pollination.