It is a border.
You could call it highlighting but more commonly you would call it selecting.
The active cell is where things will go when you start to type something into a spreadsheet.
The Active Cell on a spreadsheet is the cell where the cursor is pointing. That means that you can write to or erase the contents that cell location directly. A spreadsheet program has the entire array in memory, but the Active Cell is the place where it is 'looking or thinking about' at any particular moment.
It is the active cell.
In a spreadsheet application, it is the cell that has focus and that input can be made. The cell with the bold boundary is the active cell.
An active worksheet is a spreadsheet that is visible in a workbook. When you open a new workbook, the first sheet you see is the active worksheet.
Active Cell or Insert Location
Active cell
LED lights
it indicates
An active sheet is the worksheet you currently are accessing.
active