Answer:
The type of figurative language that is "letters" is synecdoche.
Step-by-step explanation:
Synecdoche is a figure of speech which uses a part to represent the whole and vice versa. In the passage we are analyzing, the word "letters" was a part chosen to represent a whole. Instead of saying that the students were required to wear "the clothing or objects which showcased the Greek letters of their organizations", the author chose to use "letters" as a representative of all that. An example of synecdoche frequently found on the news is when it is said that the White House has issued a report. The White House is being used to represent the people who work in it, or even the President.