... is German for: bar chart, bar graph
bar graph means: a graphical display of numbers (often called date). Each number is represented by a bar of a certain height. The height corresponds to how big the number is. If you are to draw a bar graph, you can, for example say that the number 1 gives a height of 20 millimetres. Then, logically, the number 4 would give a height of 80 millimetres. Leave a small space between neighbouring bars.
In German, a "Säulendiagramm" always means that the bars are upright (vertical) like columns or towers. In English, a bar chart or a bar graph may have the bars horizontal as well (from left to right). If you want to have a bar graph with horizontal bars in German, say "Balkendiagramm".