Histogram and Pie chart

Histogram noun - A bar chart representing a frequency distribution; heights of the bars represent observed frequencies.

Pie chart and histogram are semantically related In some cases you can use "Pie chart" instead a noun "Histogram".

Pie chart noun - A circular chart divided into triangular areas proportional to the percentages of the whole.

Histogram and pie chart are semantically related in graph resembling pie topic. You can use "Histogram" instead a noun phrase "Pie chart".