It is a drawing of a bag or sack containing a powder. In this case the it is flour. The sack looks to be sitting on a surface with the top of the bag open to show its contents.
This is a Flour 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 13,100 icons, all in the same style and quality.