Okay kiddo, have you ever seen a family's coat of arms or a picture of a knight's shield with a special picture or symbol on it? That picture or symbol is called a crest! It's like a special badge that represents a family or a group of people.
Back in the olden days, knights used crests to show which family they belonged to and which country or group of people they were fighting for. The crests were usually very colorful and had animals or objects on them that represented something important to that family or group.
Some common symbols that were used on crests include lions, eagles, swords, helmets, and shields. Each of these things had a special meaning that people could understand just by looking at the crest.
Nowadays, crests are still used for things like awards, organizations, and even some sports teams! It's still a way to show pride and belonging to a certain group or family.