Family Name, Last Name, Surname
Your clan is where you get your name. But not your given name, your family name. That's why people have names that mean "in a rice paddy" and "near the ferry crossing." The location of your clan determined your surname! Hope your ancestors didn't live on "Poo Lake" or something.
Think about your own surname in your language. Where did it come from? Were you a clan of village dwellers? Maybe you made shoes! You should look it up and find out!
し
うじ
None
Don't worry, I'll tell you where your family name came from. Your family used to herd sheep (し). You read that right, your family was of the sheep clan because you took care of sheep all day.
Imagine your ancestors, herding sheep. Thanks to them your name means "sheep people." Thanks, great-great-great-great-great-grandpappy.