It's a logo of Queue reduced to the top half of three people standing behind each other. It looks like three people waiting in line. Which is similar to what a queue is.
This Queue icon is made in flat color style
. This format was developed by Icons8 designer team and became immensely popular for use in web and mobile applications. Feel free to download this icon in PNG format for free, or unlock other formats for $5. Unlike other icon packs that have merely hundreds of icons, this monster icon pack contains 6,100 icons, all in the same style and quality.