The folks at Merriam-Webster have an interesting feature on their website showing which words are most often looked up when readers are looking for a definition.

For example, look-ups for the word “Rampart,” which Christina Aguilera forgot to sing during the National Anthem ahead of the Super Bowl on Sunday, peaked on Monday.

Look-ups for the word “Mercurial” peaked on January 22, the day after Keith Olbermann and MSNBC parted company. The word, which Merriam-Webster explains means both “changing moods quickly and often” as well as “very lively and quick,” was used to describe Olbermann in news articles and blog posts.