The children of your parent’s brothers and sisters are your cousins. There is no Dutch translation for the word ‘cousins’. We speak about ‘neven en nichten’, in that case. In English you only talk about nephews and nieces, when you want to specifically point out how many boys and girls there are in your group of cousins. For example, you might have six cousins: of these, two are nephews (male) and four are nieces (female). If your cousins have children themselves, these are your second cousins.