Your uncle's wife is your aunt and her children are presumably his children, too. They are your first cousins.
If your uncle's wife has children from a previous marriage, you are not related to them because you have no ancestors in common. However, if your uncle married her while the children were very young, they may effectively be treated as your first cousins.
If the sons of your great uncle's second wife are also your great uncle's sons, then you and they are first cousins, once removed. If her sons are from a previous or subsequent marriage (i.e. not the sons of your great uncle) then you are not related to them at all, unless your great uncle adopted them. If he adopted them, they and you are first cousins, once removed.
Yes if you will mean that uncles posses something. Examples: uncles' houses (the houses of uncles) uncles' children (the children of uncles)
Your uncles daughter would be your cousin.
Cousin. Your parents brothers and sisters are aunts and uncles. and the aunt and uncles children are your cousins.
aunties and uncles
You are not related to your uncles wife sister. However some may think an aunt
Your aunts and uncles are the sisters and brothers of your parents. So they are "blood related." But you also call the husband of your mother's sister your uncle, and he is not "blood related." So aunts and uncles are not always really related to you.
The cousins of your in-laws are not related to you and neither are their parents. However, the parents of your spouse's first cousins are your spouse's aunts and uncles, and thus your children's great aunts and great uncles.
They are your cousins.
cousin
Your uncle would be your sons great uncle. Normally your Son would also call him 'Uncle .... '
Your parent's cousins are aunts and uncles only if they have brothers or sisters who have children. Your parent's cousins are your cousins, once removed.
Your grandfather's children are either your parents or aunts or uncles.