This is the 4825th most frequent Japanese word.
浮かん
"浮かん" means "to float" or "to come to mind."
Here, '浮かん' (ukande) refers to the image of the moon appearing and seemingly floating on the water surface.
湖の水面に月が浮かんでいる。
The moon is floating on the surface of the lake.
In this context, '浮かん' is used metaphorically to describe an idea arising or coming to mind.
彼の言葉を聞いて、素晴らしいアイディアが頭に浮かんだ。
After hearing his words, a wonderful idea came to my mind.
In this sentence, '浮かん' (ukande) indicates the action of a balloon moving up and appearing to float as it rises.