This is the 4864th most frequent Japanese word.
無数
Countless; innumerable.
The word 無数 (musuu) is used to describe the immense, innumerable quantity of stars shining in the sky, emphasizing their vastness.
空には無数の星が輝いている。
Countless stars are shining in the sky.
Here, 無数 (musuu) conveys the abundant and seemingly boundless number of ideas that the person is thinking about.
彼の頭には無数のアイデアが浮かんでいる。
Countless ideas are floating in his mind.
In this sentence, 無数 (musuu) is used to highlight the multitude and uncompromising series of difficulties one has overcome.