This cannot be a rounded rectangle because those are not fully or "perfectly" rounded at the two ends. This is more like an elongated circle? A flat cylinder? I searched a lot, but among all guide
What is a Pad in PCB Design and Development
Everything You Need to Know About Gradients in Design
120 Graphic Design Terms to Help Cut Through the Jargon
A Retrospective on Shaped Watches - Revolution Watch
adobe illustrator - How to make rounded corners from shapes drawn with lines? - Graphic Design Stack Exchange
Warp images, shapes, and paths in Adobe Photoshop
shapes - Shading half a rounded rectangle in Illustrator - Graphic Design Stack Exchange
Typography Terms and Definitions
Your Rectangle / Round Rugs Shape Choice