しんずい

noun

神髄, 真髄: (figurative): The spirit or soul of something: its essence, its true quality. / 心髄: The marrow or core of something. / 神瑞: A good omen.

To understand the essence of this song, you need to listen deeply.

意味（1）

神髄, 真髄: (figurative): The spirit or soul of something: its essence, its true quality.

意味（2）

心髄: The marrow or core of something.

意味（3）

神瑞: A good omen.