There is a solid line running from north to south. a second line is perpendicular to it intersects in the center. A curved line originating from the intersection of the two strait lines begins going climbing up before turning down and going below the horizontal line before turning once more and meeting the horizontal line. Similar to a sideways S.
This is a Sine 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 13,900 icons, all in the same style and quality.