The type of figurative language that is "letters" is synecdoche.
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.
Synecdoche is a figurative language where a part is made to represent the whole. "Letters" in the above statement is a good example of synecdoche. this is because it is a part that has been substituted to stand in as a whole. The letters as explained in the statement above means clothing or objects which showcased the greek letters of their organization. So from the meaning you can deduce "letters as a part" but in the statement, it was made to stand as a whole.
