The term "18th" typically refers to the ordinal number that indicates the position of something in a sequence, specifically the one that comes after the 17th and before the 19th. It is commonly used in various contexts, such as dates, rankings, and lists. For example, the 18th day of a month signifies the day that follows the 17th. In music, "18th" can also refer to the 18th century, a period known for significant developments in classical music. Composers like Johann Sebastian Bach and Wolfgang Amadeus Mozart were prominent figures during this time, contributing to the evolution of musical styles and forms.