rainbow

including people of several different races, cultures, political beliefs, etc

Rainbow is just one of those words that radiates positivity. A rainbow is a 'nice' thing, whether real or imagined, a concept unerringly capable of making us feel warm and fuzzy inside. It's very difficult to dislike a rainbow.

rainbow describes the coming together of groups of people who are fundamentally different in terms of ethnicity, culture, sexuality or political viewpoint

It's therefore no surprise that over time the word has been embraced as a metaphor for perhaps one of the most positive human concepts of all – the idea of unity, where the rainbow's adjoining strips of colour are likened to a number of different groups of people within a unified whole.

Used as a modifier (i.e. functioning as an adjective and restricted to a position before the noun it refers to), rainbow describes the coming together of groups of people who are fundamentally different in terms of ethnicity, culture, sexuality or political viewpoint. To date, its most common collocates are the nouns alliance, coalition and nation.

The expression rainbow alliance describes groups from different backgrounds working together to achieve a common, usually political, goal. It's therefore closely related to, and often used as a synonym of, rainbow coalition, which describes a governing alliance composed of a number of different political parties. Both expressions are relatively established in US usage, where they've typically referred to collaborations involving minority and disadvantaged groups. However they've also gained ground in the UK in recent times, especially in the context of the May 2015 general election, where it was widely speculated (incorrectly, as it turns out) that no one party would gain a majority so that any new government was likely to entail some level of collaboration between two or more parties.

On the other hand a rainbow nation, in principle at least, transcends political issues and simply describes a country which contains people from many different races or cultures, a unified but distinctly multicultural, multiethnic nation.

A recent catalyst for this metaphoric sense of rainbow is its increasingly high-profile association with gay and gender rights, issues which are now often labelled with the general banner LGBT (lesbian, gay, bisexual or transgender). In June 2015, this was demonstrated in eye-catching style when the US Supreme Court's ruling on same sex marriage was celebrated by bathing several public buildings, including the White House, in spectacular rainbow lighting

Background – rainbow

Social rights activist Archbishop Desmond Tutu is credited with coinage of the expression rainbow nation, first using it in 1994 as a metaphor for post-apartheid South Africa. This later spawned the noun rainbowism, used pejoratively in South African political commentary to refer to an idealistic sense of unity and reconciliation that glosses over the real, problematic issues.

The connection between the rainbow concept and human rights is in fact older than its use in South Africa, dating at least as far back as the 1970s when it was associated with world peace and gay rights movements through the rainbow flag. Though use of the flag has had its share of controversy over the years, wider recognition of gay rights, transgender issues and the legalisation of same sex marriage have latterly raised its profile as a universal symbol of solidarity.