In a spreadsheet, which term describes a series of vertical cells?

In a spreadsheet, the term that describes a series of vertical cells is "column." A column consists of multiple cells that are stacked one on top of the other in a vertical orientation within the grid of the spreadsheet. Each column is typically designated by a letter at the top of the spreadsheet, helping users identify and reference the data contained within that column.

To understand this better, a row, in contrast, is a series of horizontal cells that run from left to right. Cells themselves are the individual units where data is stored and can be found at the intersection of rows and columns. Lastly, a sheet refers to the entire spreadsheet document rather than a specific grouping of cells. Therefore, the correct answer highlights the structured way in which data is organized in spreadsheets, focusing specifically on the vertical arrangement.