It is an arrow pointed down. The arrow is black on a solid background. There is one solid vertical line. From the bottom of that line there are two smaller black lines extending diagonally up to the right and left at 45 degree angles.
This is a Down Arrow 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.