This is the 5143rd most frequent Japanese word.
透
"透" means "transparent" or "to pass through."
Here, '透' in '透き通る' is metaphorically describing the purity or clarity of the voice's resonance.
彼の声は静かな夜に透き通るように響いた。
His voice resonated through the quiet night as if transparent.
The usage of '透' in '透り抜ける' indicates passing through or penetrating, representing movement or action.
水が岩を透り抜けて川となる。
The water passes through the rocks to form a river.
In this sentence, '透' is used within '透き通る', which means 'to be transparent', indicating a state of clarity or visibility.