4B refers to a specific classification in the educational grading system, often used to denote the fourth grade in some school systems. It typically represents a level of academic achievement and is associated with students who are around 9 to 10 years old. In some contexts, 4B can also refer to a type of pencil lead, specifically a softer lead that produces darker lines. This is commonly used in art and drafting, where varying degrees of hardness are important for achieving different shading effects.