A circle is often said to have
1 side. This is because it's a continuous curve with no breaks or angles. So, while it doesn’t have “sides” in the same way a polygon (like a triangle or square) does, it still counts as having a single, continuous side.
Some people may jokingly say a circle has 0 sides because it doesn’t have straight edges, but mathematically, it’s considered to have 1 side.