Table → Merge Cells
Use the Merge Cells command to turn one or more selected cells into a single cell (Figure 10-13). This command is not available unless more than one cell is selected. It is also not available when two cells of different sizes are selected in a freeform table. The content in any merged cells is stacked in separate paragraphs in the resulting merged cell.
Figure 10-13. Merging four identical cells into one large cell
Cells can also be merged by removing the border between the cells with the Eraser tool on the Tables and Borders toolbar. Be sure only to erase one border at a time, though, as dragging through multiple borders may also delete the content of some cells.