What Does Merging Cells Mean?

A cell is the rectangular space created by a vertical column and a horizontal row, such as in a table or spreadsheet. Merging cells creates a larger cell in the same area that was previously occupied by two or more cells.

Identification
Merging cells combines the contents of two or more cells into a single cell. The resulting cell shares the same reference (name) as the upper-left cell of the original cells and is as large as the combined space of the original cells.
 
Usage Microsoft Office Word and Excel allow users to merge cells that are in the same row or column of a table as long as the cells are adjacent. Merging cells in a row is one way to create text that spans two or more columns. Users can center the text and apply effects to create a title for the columns.

Warning Programs such as Microsoft Office Excel preserve the text in the upper-left cell only, when merging cells. The software deletes data in any other cell. Therefore, the user should move any content she wants to keep to the upper-left cell before merging any cells.