If you needed to determine how long five score is, which source would you use to define score in this context?
a) an atlas
b) a thesaurus
c) a dictionary
d) an encyclopedia

To determine the context of "how long is five score" you would use a dictionary. The dictionary will give you the definition of five score so you can figure out the correct meaning related to the context. A score is equal to 20 years. So five score would be 100 years.