Idea of Popup Icon
The image is a square that looks like a sheet of paper. There are four dashes in a vertical line on the left. To the right of the dashes are four vertical lines. There is one line to each dash. The lines and dashes are on the sheet. At the bottom of the sheet the edge comes to a point.
This Popup icon is made in Material Design style
developed by Google. This style is based on extremely simplified shapes, thin two-pixel lines, and is optimized for 24x24 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 6,200 icons, all in the same style and quality.