Once was a Rainbow

Once was a Rainbow. Yes this Character means rainbow. Modern Asian languages that use Chinese characters generally use variant sof hong/  hung 2 (Unicode 8679) but the older form is this character (Unicode 9713) NI 2 . In SinoJapanese its GEI and also niji. The oldest pronouciation was probably * nghi or ngei as the Cantonese is ngai or ai 4. Hakka is nai. Min nan ge. Korean changes this to yey and Vietnamese to nghi. Like many other classicla older forms its become neglected in favor of characters with less strokes easier to remember and write.

If you look at the seal script its tempting  to think the original sign was read as a rainbow or any multicolored haze or cloud in the sky, the other meaning of the word, being  the child of the sky or rain.