The term "4-" typically refers to a prefix used in various contexts, such as in chemistry or mathematics. In chemistry, it can denote a specific position of a substituent on a benzene ring, indicating that the substituent is located at the fourth carbon atom relative to another reference point. This is important for understanding the structure and reactivity of organic compounds. In mathematics, "4-" can be used as a shorthand notation to indicate a value that is four units less than a given number. For example, if you have the number x, then "4-" would represent x - 4. This type of notation is useful in equations and problem-solving scenarios where adjustments to values are necessary.