In optical retail, what does the term "frame material" refer to?

The term "frame material" specifically refers to the substance used to create the eyewear frames. This encompasses a variety of materials such as plastic, metal, titanium, and acetate, each of which has distinct characteristics influencing the frame's weight, flexibility, durability, and aesthetic appeal. Understanding the different frame materials is crucial for making informed recommendations to customers, as it affects not only the frame's performance and comfort but also its suitability for different styles and fashion preferences.

Other options refer to attributes that do not define "frame material." The color of the frame pertains to its visual appearance, the style describes its design and shape, and the brand relates to the manufacturer or company producing the eyewear. While these aspects are important in the context of eyewear, they do not convey the specific meaning of frame material.