Homonym: O (Circle)
The letter "O" is the 15th letter of the English alphabet. It is a vowel and is often used in various words to create sounds. In the English language, "O" can represent different sounds, such as in "hot" or "go."
In mathematics, "O" can also refer to the big O notation, which describes the performance or complexity of an algorithm. This notation helps in analyzing how the runtime or space requirements of an algorithm grow as the input size increases.