The term active cell describes any cell that you have selected and highlighted in your spreadsheet. Data can be entered or formatted in an active cell, without modifying the rest of your sheet.
Figure 1: Example of active cell
More than one active cell is called a range, which can be either continuous or non-continuous. Active cells that are all adjacent to each other signify a continuous range. To define a continuous range, click on an active cell and drag your cursor to highlight neighboring cells.
Figure 2: Example of continuous range
Active cells that have gaps between them form a non-continuous range. To define a non-continuous range, press and hold down the Control key (Command Key for Mac users) and click and drag your cursor to highlight cells.
Figure 3: Example of a non-continuous range