property Items.ItemCell (Item as HITEM, ColIndex as Variant) as HCELL

Retrieves the cell's handle given the item and the column.

Item as HITEM A long expression that indicates the item's handle.
ColIndex as Variant A long expression that indicates the the column's index, a string expression that indicates the column's caption or the column's key.
HCELL A long value that indicates the cell's handle.
The ItemCell property retrieves the handle of the cell that belongs to the item on the specified column. The InnerCell properties always returns the handle to the master cells ( master cell is a cell where the splitting starts ). Use the SplitCell property to split a cell into multiple cells. Use the MergeCells property to merge multiple cells. 

Note: The intersection of an item with a column defines a cell. Each cell is uniquely represented by its handle. The cell's handle is of HCELL type, that's equivalent with a long type. All properties of Items object that have two parameters Item and ColIndex, refer a cell.

The following lines are equivalents and each of them changes the bold font attribute of the first cell on the first item.

With Grid1
    .Items.CellBold(, .Items.ItemCell(.Items(0), 0)) = True
    .Items.CellBold(.Items(0), 0) = True
    .Items.CellBold(.Items(0)) = True
    .Items.CellBold(.Items.ItemByIndex(0)) = True
    .Items.CellBold(.Items.ItemByIndex(0), 0) = True
    .Items.CellBold(.Items(0), Grid1.Columns(0).Caption) = True
End With