Origin

This character combines water (the left side) with a sound component on the right that tells you it's pronounced roughly "ran." The water radical acts as a classifier, showing this character relates to liquid or flow. The meaning of excessive or overflowing comes from imagining water that spreads out uncontrollably beyond its proper bounds—water that ignores limits and floods everywhere. The sense of something being excessive or unregulated grew from this core image of water without restraint.