A Word Cloud is a graphical representation of word frequency.
A Word Cloud Generator is a tool that can be used to create visualizations from blocks of text. The clouds give greater prominence to words that appear more often in the text.
Word Clouds can be used to help students vary word choice in their own writing by highlighting words they use frequently. They can also be used to highlight themes in text by giving greater prominence to words that appear most often.
Most Word Cloud Generators allow you to personalize your cloud with different fonts, layouts, and color schemes.
Below are a couple of Word Cloud Generator options.
For Google Chrome: