Here's why:

* Cirrus refers to high-level clouds (above 6,000 meters).

* Stratus refers to clouds that form in flat sheets or layers.

Cirrostratus clouds are thin and veil-like, often covering the entire sky. They can appear grayish, but they also can be translucent, allowing sunlight to pass through. They are often associated with approaching warm fronts or a change in weather.

Other types of high-level clouds that might appear grayish include:

* Cirrocumulus: These clouds are composed of small, rounded puffs arranged in a pattern, sometimes resembling fish scales. While typically white, they can appear grayish depending on lighting.

* Altostratus: These clouds are higher than altocumulus but lower than cirrostratus, appearing as a gray or bluish sheet.

It's important to remember that cloud identification can be complex, and the appearance of a cloud can vary significantly based on factors like lighting, altitude, and composition.