The ____________________ is a small black square in the lower-right corner of the active cell or active range.

Fill Handle

A tool in spreadsheet software used to automatically fill in cells with data based on the pattern of existing data.

Active Cell

In spreadsheet applications, the currently selected cell where data can be entered or edited.

Active Range

In computing, the active range refers to the currently selected group of cells or area in a spreadsheet where operations can be performed.