How to Use "semicircle" with Example Sentences

1. They sat in a semicircle .
2. They are sitting in a semicircle .
3. We sat in semicircle aboutthe fire .
4. Inside , though , as we gathered in a semicircle around the bed , I doubted my words .
5. An air bubble ascending from the ocean floor contorts and twists into a semicircle as a wave breaks in the background .