What does the term "first cousin once removed mean? Does it mean that my first cousin “L” who had a child “B” that child is my 1st cousin-once removed? It would then follow that if “B” had a child it would be my first cousin -twice removed? (and I’d be old!)
So then, my Grandmothers sisters are my Great Aunts. Their offspring would be my Mums first cousins and my second? If so, how do you get 3rd and fourths? Besides being very uxorious I mean. 
A post on this from Friday. I’m all for reintroducing topics, but I don’t believe there have been significant insights on this matter in the last 72 hours.
You get extra relatives for being a slave to your wife?
I never knew that.
Not quite. Your great aunt’s offspring are indeed your mom’s 1[sup]st[/sup] cousins. They and you are 1[sup]st[/sup] cousins once removed. If they have children (your great aunt’s grandchildren), they are your 2[sup]nd[/sup] cousins.
Following this pattern, 3[sup]rd[/sup] cousins have great-grandparents that are siblings, 4[sup]th[/sup] cousins have great-great-grandparents that are siblings, and 5[sup]th[/sup] cousins (like Presidents Teddy and Franklin Roosevelt) have great-great-great-grandparents that were siblings.
Let’s make this simple.
Your first cousin’s child is your first cousin, once removed.
Your first cousin’s grandchild is your first cousin, twice removed.
Your child, and your first cousin’s child, are second cousins.
Your child, and your first cousin’s grandchild, are second cousins, once removed.
When two people are descended the same number of generations from a common ancestor, we use terms like first cousin, second cousin, third cousin, etc.
When two people are descended an unequal number of generations from a common ancestor, we add “removed” to describe the inequality.