whirl, swirl
匯 centers on circular, gathering motion: a whirl or swirl, often of water or currents.
匯 combines 匚 (a container or enclosure) with 淮, which likely contributes the sound and relates to water. The idea of water swirling within a confined space fits the meaning.
The outer enclosure 匚 acts like a basin, and inside it 淮 (a water-related shape) swirls around. Picture water whirling inside a container.
For キ, imagine a key swirling in a whirlpool: key -> キ, and the water spins around it.