When I tell people that I use strawberry sepals in my collages they always ask "What's a sepal"?
If you aren't ready to search the dictionary I can tell you that it's part of the structure of a flower. They're the leafy green parts that add to the form of the calyx. Look up 'flower' and you will usually find a simple illustration of the parts of a flower.
I cut the sepals from the strawberries and then use a process to clean and preserve them. Here they are right after being cut from the strawberry.