説明書

To wake up to something you had not seen. 悟り is enlightenment in the Buddhist sense.

Sound, including music. 音楽 is music; 発音 is pronunciation.

Half of 瑠璃, the deep blue stone. On its own it is used mostly for its sound and its colour.

The character in 武士道, the way of the samurai, and in 柔道. Read dō, and the head of it is taken for do.