This is an icon for an onion. The onion has layers and layers that is revealed. There appears to be five layers on the onion and on the outside of the onion there appears to be the root of the onion.
This page contains the Onion vector icon, as well as variations of this icon in different visual styles, and related icons. All icons are in the flat vector style, however, differ by the line thickness, fill, and corner radius.