What term means preventing light from traveling through?

The term that means preventing light from traveling through is "opaque." Opaque materials do not allow light to pass through them at all, resulting in a complete blockage of any light. This is in contrast to translucent materials, which permit some light to pass through but scatter it, allowing objects on the other side to appear blurred. Transparent materials, on the other hand, allow light to pass through clearly, enabling a clear view of objects behind them. The term "clear" often describes something that is free from obstruction and can include various states of visibility but does not specifically refer to the property of blocking light. Thus, "opaque" is the most accurate term to indicate a material that prevents light from traveling through.