label
labels
It is called Autocomplete.
In Excel, it means entering something in a cell.
A formula.
cell splitting
Right-aligned
Z is not a number.
cell contents
It can be called autofit or if you are specifically shortening it, it can be called truncation or you may round down a number to reduce the amount of decimal places.
To cancel an entire entry before entering it into an Excel cell, hit the Esc key or click on the Cancel button on the formula bar, which is the red x.
Cell Reference
It changes to Edit mode.
lavel