histogram vs pie chart

histogram

noun
  • A graphical display of numerical data in the form of upright bars, with the area of each bar representing frequency. 

verb
  • To represent (data) as a histogram. 

pie chart

noun
  • A pictorial graph in the shape of a circle, with segments representing related proportions 

How often have the words histogram and pie chart occurred in a corpus of books? (source: Google Ngram Viewer )