ceremonial libation cup
瓚 centers on a ceremonial libation cup, a ritual vessel used for pouring offerings. The meaning is narrow and specific to this object.
瓚 combines 王 (jewel, here representing precious material) with 贊, which likely contributes the sound. The character denotes a ceremonial jade cup used in libations.
The left side 王 suggests a precious jade object, and the right side 贊 hints at assisting in a ceremony. Picture a beautiful jade cup used to pour ritual offerings.
For サン, imagine the sun (サン) shining on a ceremonial cup during a ritual: sun -> サン, and the cup gleams in the sunlight.
—