Okay kiddo, so Bertil is actually not a thing, it's a name for someone. You know how you have a name like "Emma" or "Jack"? Well, Bertil is just another name like that.
Now, let's talk about the origin of the name. Bertil comes from a country called Sweden, where they speak a language called Swedish. In Swedish, the name Bertil means "bright as a day", which is a really nice meaning!
So, there might be a person you meet someday named Bertil, and you'll know that his name comes from Sweden and means "bright as a day". But remember, Bertil is just a name for a person, not a thing like a toy or a car.