to be transparent; to be see-through — to allow light or vision through so that things can be seen clearly.
川の水が透き通っていて、底の石まで見える。
The river water is so clear that you can see the stones at the bottom.
そのガラスは古いが、まだ透き通っている。
That glass is old, but it's still transparent.
彼女の肌は透き通るように白い。
Her skin is white as if transparent.
to be clear (of a voice or sound) — a sound that is pure, bright, and carries well.
彼女の歌声は高く透き通っていて心に響く。
Her singing voice is high and clear, and it resonates in the heart.
夜の静けさの中でピアノの音が透き通って聞こえた。
In the quiet of the night, the piano sounded clear and pure.
録音がきれいで、ボーカルの声が透き通っている。
The recording is good and the vocalist's voice is very clear.