Many languages do not distinguish between what in English are described as "blue" and "green". They instead use a cover term spanning both. When the issue is discussed in linguistics, this cover term is sometimes called grue in English.
The exact definition of "blue" and "green" may be complicated by the speakers not primarily distinguishing the hue, but using terms that describe other color components such as saturation and luminosity, or other properties of the object being described. For example, "blue" and "green" might be distinguished, but a single term might be used for both if the color is dark. Furthermore, green might be associated with yellow, and blue with black or gray.
According to Brent Berlin and Paul Kay's 1969 study Basic Color Terms: Their Universality and Evolution, distinct terms for brown, purple, pink, orange and grey will not emerge in a language until the language has made a distinction between green and blue. In their account of the development of color terms the first terms to emerge are those for white/black (or light/dark), red and green/yellow.
The word for blue in Amazigh language is Azerwal. In some dialects of Amazigh, like Shelha, the word Azegzaw is used for both green and blue.
The color of the sky is sometimes referred to as "the green" in Classical Arabic poetry, in which al-khaḍrā’ (الخضراء). In Arabic the word for blue is generally azraq (أزرق). The Arabic word for green is akhḍar (أخضر).
In Moroccan Arabic, the word for light blue is šíbi, whereas zraq (زرق) stands for blue and khḍar (خضر) for green. The word zrag (زرڭ) is used to describe the color of a suffocated person, and is also used pejoratively as synonym to "dumb".