The phrase "gesture feature" refers to a function or capability of a device that allows users to control or interact with it through physical movements or gestures, instead of using buttons or touch. Full definition
The Air gestures feature on this device uses the front - facing camera to detect the wave gestures. (phoneradar.com)
It does also include some new tweaks such as an update to live wallpaper and a fingerprint gesture feature, which was previously exclusive to Pixel devices. (ibtimes.com)
Moving to the front, you'll see the front - facing speaker, and two noticeable dots below the display, that are sensors to help with the air gesture features. (androidauthority.com)