rainbow

[Yendred]

the Ancient Greeks called it «ἶρις» /îːris/ (fem.).

The etymology is confusing (probably from PIE), but interestingly, it's also the name of the Goddess Iris, personification of the rainbow, and messenger of the gods.
It is said that when she descended from Olympus to earth to carry a message, her foot was leaving a trace in the sky, a rainbow, symbolizing the link between gods and humans.

 

[apmoy70]

The name hasn't survived in MoGr (for describing the rainbow) bar the name for the iris of the eye = «ίριδα» [ˈi.ɾiða] (fem.) < oblique «ἰριδ-» /irid-/ of the 3rd declension ancient noun «ἶρις» /ˈîː.ris/ (fem. nom. sing.), «ἴριδος» /ˈi.ridos/ (fem. gen. sing.), and in the set-phrase for describing the colours of the rainbow = «χρώματα της ίριδος» [ˈxɾo̞.mat̠aˌt̠is̠ˈi.ɾiðo̞s̠].

 

[Yendred]

Yes in European languages, we also have iridescent/iridescence (= like the colours of the rainbow or of the iris of the eye).

 

[alfaalfa]

Ciao

Italian: arcobaleno ("arco"="arch";"baleno"="flash, lightning")

We have iride and iridescente too.

 

[Yendred]

Italian: arcobaleno ("arco"="arch";"baleno"="flash, lightning")

The etymology of this one is interesting. Balena means whale in Italian, and the connection comes from the popular habit of indicating atmospherical phenomena using the names of sea monsters.

 

[alfaalfa]

Hmhm. I'm not an expert but I think baleno has a different etymology
Etimologia : balenare;

 

[Yendred]

Right, the connection with balena is indicated as uncertain on the English wiktionary:
balenare - Wiktionary, the free dictionary

 

[Welsh_Sion]

Seems as if @Yendred's thread has fused with a previous thread on 'rainbows'.

Here's my little contribution:

Cymraeg/Welsh

enfys /'ɛnvɨs/ (n.f.m.) Etymology, Celtic. cf. BZH. envez
Historically, Bwa'r (n.m.) Arch /'bu:ar arX/ 'Bow of the Ark*'

*Noah's (obviously).

English

Side track into English. Traditionally, many English learn (or at least, used to learn) this expression referencing the Battle of Bosworth (1485) to remember the colours of the rainbow:

Richard - Red
Of - Orange
York - Yellow
Gave - Green
Battle - Blue
In - Indigo
Vain - Violet

Any other mnemonics in other languages?

 

[Yendred]

Any other mnemonics in other languages?

There are a few of them in French, for example:

Vous - Violet
Inventez - Indigo
Bien - Bleu
Vous - Vert
Jeune - Jaune
Oisif - Orange
Ridicule - Rouge

It's the reverse order of the English sentence, and the problem is that there are two colours that start with a V.

 

[Yendred]

enfys /'ɛnvɨs/ (n.f.m.) Etymology, Celtic. cf. BZH. envez

Literally "ring" ("in-finger"), isn't it?

 

[Welsh_Sion]

Literally "ring" ("in-finger"), isn't it?

More like 'large ring'. See GPC 'enfys'. But not completely sure: Geiriadur Prifysgol Cymru

 

[kwak22]

Vasmer suggests the Russian word "радуга" most likely comes from "рад" (happy), mentioning the jolly look of a rainbow and popular incantations that are inspired by it.

Any other mnemonics in other languages?

Каждый (Every) <-> Красный (Red)
Охотник (Hunter) <-> Оранжевый (Orange)
Желает (Desires) <-> Жёлтый (Yellow)
Знать, (to Know) <-> Зелёный (Green)
Где (Where) <-> Голубой (Light Blue)
Сидит (is Sitting) <-> Синий (Intense Blue)
Фазан (a Pheasant) <-> Фиолетовый (Violet)