One aspect of worldbuilding that is often ignored (alongside music/poetry, visual art, and food; all of which will receive their own s at some point) is colour in a _cultural context_.

So let's have a chat about that, shall we?

You see, colour is neither well defined nor conceptually static cross-culturally. A culture may define very few colours, such as Berinmo (3 colours, 2 tones), whilst others like English define many more. Some, such as Pirahã have no colours, but terms for shades of "brightness".

So from a very fundamental level, the _idea_ of colour is culturally grounded, thus meaning assumptions like "black is for mourning and death" is a wildly nonsense thing to apply to a fantasy world.

Even on Earth, between languages (and associated culture) that have very similar colour divisions (such as English and Japanese), we have a wide range of interpretation: in most English-speaking countries, white suggests cleanliness and "virginity" (e.g. wedding dresses), but...

...in Japan, white tends to be associated with death (which makes sense, given bones are white). Of course, this changes as cultures interact, but that interaction itself is interesting: imagine the first Japanese wedding where the bride wanted to wear a white dress!

These colour correlations tend to revolve around context. Green is a great example: in Islam, green is a divine colour. Which makes sense, when you consider Islam arose in a region where greenery was comparatively rare, and places which were green (and therefore had water)...

...would not be _assumed_, as they would be in Europe where green is abundant. And because green = divine in Islam, many Islamic armies wore green or used green in their heraldry during the Crusades to gain divine favour, which lead to Christian crusaders _avoiding_ green.

Of course, green was already avoided in most Christian heraldries, because most Christians were fighting on battlefields (pre-Crusades) in areas which were overwhelmingly green, and heraldries are used to pick people out of a complex backdrop in combat.

A green tabard on a green hill does not make an easy battle to follow, does it?

But because the Muslims were fighting in green, green took on a worse association for Christians during the Crusades (and somewhat since). Green became the "wilds" which are pushed back.

But I digress: groups assign meaning to colours based on their contexts, and based on their neighbours. If a culture likes red, because they have a flower that grows in their lands that makes a very beautiful red dye, then the people who hate them likely don't use much red.

For culture 1, red is probably a colour of wealth and abundance. For culture 2, red might be a colour of aggression or dominance, or maybe cowardice (if they think their neighbours are craven, etc.).

What I'm saying is: look at where your culture is, think about the colours they are finding in their environment, question which colours they want to see and why, and which colours blend into the background for them. Then do the same for the neighbours, and compare notes.

THEN, once you have your colour library, show it off in every way you can! Make your aristocrats wear the wealthy colour, your hopeful youths the wedding colour, your mourning priests the sad colour, etc.