The term "oh" is an interjection commonly used in the English language. It expresses a range of emotions, including surprise, realization, or disappointment. People often use "oh" to react to unexpected information or to acknowledge something they have just understood. In written communication, "oh" can also convey tone and emotion, helping to clarify the speaker's feelings. It is frequently found in conversations, literature, and even song lyrics, making it a versatile expression in everyday language. Its simplicity allows it to be easily understood across different contexts.