The letters "a," "b," and "c" are the first three letters of the English alphabet. They are used in various contexts, including language, mathematics, and music. In the alphabet, "a" is the first letter, "b" is the second, and "c" is the third, forming the foundation for spelling and pronunciation. In music, the notes A, B, and C represent specific pitches. These notes are part of the diatonic scale, which is essential for creating melodies and harmonies. Additionally, in mathematics, "a," "b," and "c" are often used as variables in equations and formulas.