Lotty is a nickname that some people use for names like Charlotte or Lillian.
When you are born, your parents choose a special name for you. Sometimes, these names can be long or have a lot of letters in them. So, they might give you a shorter, easier-to-say nickname to use instead.
For example, let's imagine there is a little girl named Charlotte. That's a big word for a little girl to say! So her family might decide to call her "Lotty" instead. It sounds similar, but it's much easier for her to say and remember.
Some other names that might use "Lotty" as a nickname are Lillian or Loretta. These names can also be a mouthful for a little kid, so their families might use the nickname "Lotty" instead.
Nicknames are a special way for families and friends to show love and make each other feel special. So if you meet someone named Charlotte or Lillian and they ask you to call them "Lotty," you now know why!