Definitions for "Connected component"
In a graph, a (connected) component is a maximal, connected, induced subgraph. Maximal means that there is no larger connected, induced subgraph containing the vertices of the component.
a maximal collection of pixels such that a path exists between any pair of pixels in the component
a maximal connected set of vertices
Keywords:  lifted, rest, buttons, set, one
a connected set of buttons such that if one were lifted up, the rest would be lifted with it