O

The letter "O" can represent different concepts depending on the context, but in general knowledge, it often stands for "Order of Operations" in mathematics, which is a set of rules that indicates the sequence in which calculations should be performed. It's important for obtaining correct answers when solving mathematical expressions. "O" can also symbolize other concepts, such as "oxygen" in science or "octagon" in geometry, reflecting its versatile use across various fields. Understanding the context in which "O" is used is key to grasping its meaning.