etymology - Origin of the of the phrase feeling blue - English . . . If you are sad and describe yourself as "feeling blue," you are using a phrase coined from a custom among many old deepwater sailing ships If the ship lost the captain or any of the officers during its voyage, she would fly blue flags and have a blue band painted along her entire hull when returning to home port Also, see Origins of Navy Terminology for other expressions
Why does blue blazes specify the color blue, and what is the origin . . . The Wikipedia article on sulfur confirms the flame color: Sulfur burns with a blue flame with formation of sulfur dioxide, which has a suffocating and irritating odor But is that the original rationale for "blue blazes"? Also, when and where did the earliest recorded instances of "blue blazes" and "blue blazes of hell" occur?
Why are Australian redheads often called bluey? - slang The Virgin Blue name was the result of an open competition; it was a play on the predominantly red livery and the Australian slang tradition of calling a red-headed male 'Blue' or 'Bluey' This is confirmed on other sites such as this one How did blue come to represent red in Australia?
etymology - What is the origin of the term red team for a group . . . 9 In information security, the military, etc , a "red team" is a group that plays the role of an adversary in a simulated engagement (with the "blue team" on the other side of the engagement) What is the origin of this term?
Where did the phrase blue sky thinking come from? The true origin is what you’d expect in a business setting: In the early 20th century, “blue sky” was frequently applied to describe fraud — notably, financiers who would inflate and over-capitalize securities based on nothing more tangible than “blue sky and hot air ”
Origin of blue for rude? - English Language Usage Stack Exchange The phrase “working blue” came into usage at the time If a representative of the Keith Orpheum circuit objected to the content of an act, a request to cut the material was sent backstage in a blue envelope So-called blue material was considered problematic enough that vaudeville listings in local papers noted which shows were “Clean
Why do we say that an obscene joke is off-color? Here is the definition of off color in Chapman Kipfer, Dictionary of American Slang, Third Edition (1995): off color adj phr by 1875 Somewhat salacious; risqué; =BLUE: a couple of off-color jokes Some of his observations were a bit off color That same reference reports that blue in the sense of "lewd, rude, suggestive" appeared in American English by 1840 The same sense of blue appears