Endogamy in Jewish families made (and makes) for multiple ways in which family members are related.  My great-grandfather Avrohom’s first wife Esther died after having four daughters.  Then, following a custom of the time, Avrohom married Esther’s younger sister Liba and had eight more children, one of the eight being my grandfather Jacob.  Then Esther’s eldest daughter Sarah Malke married her mother’s brother Aron – that is, Sarah Malke married her uncle, a marriage allowed under religious law.   Sarah Malke and Aron had eight children.   As a result, my grandfather can be viewed as both an uncle and a cousin to those children – an uncle on their mother’s side (since he is Sarah Malke’s ¾ brother) and a first cousin on their father’s side (since his mother Liba is a sister to Sarah Malke’s mother Esther).   When I was growing up, I could not figure out why so many people in our family’s “cousins’ club” called my grandfather “Uncle Jake” – I thought this was a title placed on him due to his age.  But, when we sorted out the relationships in the family, It was clear he was the uncle of these people (and granduncle to their children) as well as their cousin.