Various cultures divide the semantic field of colors differently from the English language usage and some do not distinguish between blue and green in the same way. An example is Welsh where  can mean blue or green, or Vietnamese where  likewise can mean either. Conversely, in Russian and some other languages, there is no single word for blue, but rather different words for light blue (, ) and dark blue (, ).
Other color names assigned to bodies of water are sea green and ultramarine blue. Unusual oceanic colorings have given rise to the terms red tide and black tide.
The Ancient Greek poet Homer uses the epithet "wine-dark sea"; in addition, he also describes the sea as "grey". William Ewart Gladstone has suggested that this is due to the Ancient Greeks classifying colors primarily by luminosity rather than hue, while others believe Homer was color blind.
The Ancient Indian Wisdom of Veda consider life giving contributions of water a part of divine and recognize water as a primeval God Varuna; and the color of Varuna is described as blue. In the Gayatri associated with Varuna, the word "neela purusha" comes in second line which calls the water deity, the blue one.