It's a logo of No Entry reduced to a rectangle enclosed by a circle. The logo is placed in a rounded circle. Looking like the no entry sign seen on the roads.
This is a No Entry icon. We've made it in iOS style
, first introduced in iOS version 7 and supported in all later releases up until now (at least iOS 11). This style is based on thin two-pixel lines and is optimized for 50x50 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 13,300 icons, all in the same style and quality.