blue
UK[bluː]US[bluː]
adj
Of the colour of a clear sky or the deep sea on a sunny day.
adj
(informal) Sad, melancholy, or depressed.
n
The colour of a clear sky or the deep sea, one of the primary colours.
Etymology
The word 'blue' entered English from the Old French 'bleu' or 'blou', which itself derived from a Germanic source, likely Frankish blāo. This Germanic root is traceable back to the Proto-Germanic blēwaz, meaning 'dark blue' or 'black'. The ultimate origin is the Proto-Indo-European root bhel-, meaning 'to shine, flash, or burn', which also gave rise to words for pale or light colours like 'blond' and 'blank'. The semantic journey from a root meaning 'shine' to a specific colour name is a common phenomenon in language evolution, where a quality (like brightness) becomes associated with a particular hue. The figurative sense of 'sad' or 'melancholy' emerged in the late 18th century, likely from the association of the colour with low spirits, as seen in the phrase 'the blues'.
Analysis
The word 'blue' is a simplex word of Germanic origin. It cannot be meaningfully segmented into distinct morphemes in modern English.
Examples
The artist mixed white with blue to create a perfect sky colour.
She felt a little blue after her friends went home.
He decorated his room in various shades of blue.