I can tell you what it is but without a picture i can not help you.
A cross section of anything is when the shape is getting cut straight into an object. It is like viewing the inside of something made by cutting through the object.
Answer:
The picture doesn't work but tell me in the comments what it is and i will gladly help you out. Please mark me the brainliest answer?
<3 Hoped this helped!!!! Have a good day!!! :D