1.
purple, violet (color)
A color between red and blue.
紫 is the color purple. In traditional Japan, purple was associated with nobility and high rank.
Common expressions
Sushi restaurant slang
紫 is used to mean 'soy sauce' at sushi restaurants, along with other special terms like:
Etymology
Purple dye was expensive and difficult to produce, so 紫 became associated with royalty and high status in Japan.