What is the Greek letter associated with the symbol "I"?

The Greek letter associated with the symbol "I" is indeed Iota. In the Greek alphabet, Iota is the ninth letter, which corresponds to the Latin letter "I." Each letter in the Greek alphabet has its own distinct sound and significance within various contexts, such as mathematics, science, and fraternity or sorority names.

The other letters mentioned—Mu, N, and Lambda—are separate and distinct letters in the Greek alphabet with their own specific identifiers and meanings. Mu corresponds to the letter "M," N corresponds to "N," and Lambda represents "L." These letters do not represent the symbol "I," highlighting the unique identity and representation of Iota in the Greek language and culture.