Just reading about Mary and Joseph who both have genealogies that take them back through the Kingly line to David. However, Luke describes Elizabeth as cousin to Mary and her descent was from the daughters of Aaron. Zachariah was a descendant of Abijah the priest. Were Mary and Elizabeth cousins as we would understand cousins (i.e. their parents were siblings)?
The relationship you describe is that of first cousins. Mary and Elizabeth were what we would call cousins “many times removed.” The Greek word translated “cousin” in Luke 1:36 can mean anything from the offspring of siblings to a fellow countryman. Their blood relationship stems from the fact that Elizabeth’s ancestor Levi was the brother of Mary’s ancestor Judah.