Notch

A "notch" refers to a physical area reserved for sensor(s) on the display of a device, usually at the top. This has become a design element of since 2017, balancing the need for front-facing cameras, microphones, and/or other sensors with consumer demand for larger edge-to-edge screens.

Background
The (PH-1), announced in May 2017 and released in August, was the first mobile device to implement a "waterdrop" style notch to mixed reviews. Then Apple's introduction of the wide notch on the iPhone X, announced in September 2017 and released in November, popularized the design. Android phone manufacturers implemented various approaches, ranging from a "holepunch" style to a mechanical pop-up or slider to hide the front-facing camera and sensors when not in use.

Hiding the notch
3rd-party developers have created software to obscure the "notch" in iOS and macOS by blacking out the horizontal area around it.