far and wide, cycle, period
浹 centers on something that extends broadly or completely, like water spreading far and wide. The cycle and period senses are less common and may be specialized applications of this idea of thorough coverage.
浹 combines 氵 (water) with 夾, which likely contributes the sound and the idea of being between or on both sides, suggesting water spreading everywhere.
Water 氵 plus 夾 (which looks like a person carrying things on both sides) suggests water spreading far and wide, covering everything.
For ショウ, imagine a show of water spreading across a vast stage: show -> ショウ, and the water reaches every corner.