This is a Week View 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 12,300 icons, all in the same style and quality.
There is a rectangle, split horizontally towards the top once and split vertically with five lines. This separates the rectangle into six small squares at the at the top, with six longer vertical rectangles underneath, much like a calendar.