What term describes the area within or surrounding a hair design?

The correct answer is "space," which refers to the area within or surrounding a hair design. In the context of hair design, space is critical as it can influence how the overall hairstyle is perceived. Understanding the space around a hairstyle allows stylists to create balance and harmony, helping to highlight the design features while ensuring the hairstyle complements the client's face shape and proportions.

The term "outline" generally focuses on the outer shape or contour of the hairstyle rather than the area surrounding it, making it less relevant in this context. "Background" usually pertains to the setting or context in which something exists, but it is not as specific to the design aspect of hairstyling. Lastly, "zone" could refer to specific areas of the head being styled or sections of hair, but it does not encompass the broader concept of area surrounding the design like "space" does. Understanding these distinctions is vital for effective communication and execution in hair design.