Something is wrong
Sam Explains the Difference Between Name and Family Name
That is a lovely idea
Mormont is a last name
Why is it a last name?
Well, it's a family name.
For instance, I'm Samwell Tarly.
Samwell is my birth name
And Tarly is my family name.
You see? So, my father is also a Tarly.
Tap on unfamiliar word.
Backstory: After a riot at Craster's castle, Sam, Lily and her newborn son, find an abandoned house for the night. When asked about the child's name, he figure out that Lily does not understand what a name and what a last name is.