If you are talking about an individual cell it's a field.
If you are talking about the whole thing, that is your spread sheet.
Range or Block
a grid in a rectangular shape with a x axis and a y axis.
In geometry, a rectangular solid is called a rectangular solid. A cube is a rectangular solid that happens to have all surfaces equal.
A rectangular prism?
The pair of numbers used to locate a point on a grid is called coordinate points.
A polyhedron with six faces is often called a cuboid. It is also called a rectangular parallelepiped or a rectangular hexahedron, or sometimes simply, a box.
A rectangular group of cells in a spreadsheet can be called a range or a block.
a grid in a rectangular shape with a x axis and a y axis.
speadsheet
columnar
The grid is a rectangular pattern of dots or lines that extends over the area you specify as the grid limits. The grid displays dots only when the current visual style is set to 2D.
column
When viewing a cork through his homemade microscope Robert Hook discovered small compartments that he called cells.
A worksheet. Some people may also refer to a table, which would be a specific rectangular set of cells within a worksheet used for a particular purpose.
Grid Line
The introduction of a solar power plant helped me to get off of the electric power grid permanently. This grid is rectangular, not square.
A group of cells is called a range.
When you look at a worksheet in Excel you can see all the cells, because of the lines around them. Those are gridlines. You can also add borders, to make heavier lines around cells. Gridlines can be turned off completely, by going to the Options menu and the View section and removing the tick beside Gridlines.