Meaning: The sentence portrays a cloud moving serenely through the vast expanse above.
Choice of Words: The word "cloud" refers to a visible mass of tiny water droplets or ice crystals suspended in the atmosphere. "Floated" means to move smoothly and effortlessly through the air or water. "Peacefully" means in a calm and tranquil manner. "Across" indicates movement from one side to the other. "Sky" is the open space above the earth.