Why does "blue" mean "obscene"?

As in “blue humor,” “blue movies,” etc. (And yet, at the same time, “blue laws” are religious-morality laws and a “bluenose” is a moral reformer.)

According to this Wikipedia article (which you may take with as many grains of salt as you like), “The term comes from the music hall comedian Max Miller who kept all his adult jokes in a blue coloured notebook.”

http://www.snopes.com/language/colors/bluelaws.asp Snopes and a couple other sites take it back to the Puritans.

Which are laws prohibiting exactly the sort of thing that blue humor deals with. I don’t see a conflict at all between the two usages.

I’m not buying the Max Miller thing, since the term “Blue Stocking” referring to an overly educated/intelligent woman was commonly understood terminology long before his birth.

The first reference I can find (in admittedly quick, lazy search) is 1871 in an article by Samuel Peters – over 100 years before Max was even a twinkle.

I do have a vague recollection of earlier references to “bluenose” being a disparaging term for a totally uptight old prig, but that dates (roughly) to about the time of my switch from History to Anthropology as a major, so I wouldn’t like to bet it’s an accurate memory.

The OED seems to have the earliest cite from 1824, and from a Scottish source, so it may not be American at all.

It may be related to “bluestocking,” which dates from 1790 and meant a “refined” woman, known for their contempt of more mundane life. Blue humor would upset the bluestockings.

OED

Seems like it was used in the sense you want it by 1824.

1771. I’m a bad-typing, nonproofreading dumbass.

My high school Spanish teacher amused the class by telling us that the Spanish equivalent was “es verde” or green. I haven’t checked this as it’s the one thing from high school Spanish I remember and I don’t want to spoil that.

What I find amusing is that in Chinese, “yellow” is the equivalent term. (Cue mass of confusion when first generation Chinese read about “yellow journalism” and get the wrong idea.)

Possible related question: Would the use of “blue” here be in any way related to the concept of “feeling blue?” I realize that in the OP’s sense it is obscene/dirty and in this one it’s intended as feeling sad, but it seems like they should share a common etymology since they are both used to indicate a negative sentiment.

While we’re at it, where does “blue blood” fit in? Anywhere?

Different origin. Aristocrats would avoid the sun as far as humanly possible so noone could mistake them for common labourers, and their veins looked blue through the pale skin.

Ah – so that’s why the aristocracy was always depicted as being so pale. Makes sense.

So what of “feeling blue” then?

By 100 years later (1971), Max was already dead.

David Dodge, author of humorous travel books, wrote a book in the late 1940s about his family’s adventures in Mexico. It seems that in every Mexican city he visited, he saw billboards advertising a movie called Que verde era mi padre – literally “How Green Was My Father”, which became the title of his book. At the time, he assumed the movie’s title was a take-off on How Green Was My Valley. Later he learned that verde was Spanish slang for “dirty” in a sexual sense. Viejo verde is the Spanish equivalent of “dirty old man.”

BTW, David Dodge also wrote the novel on which the Hitchcock film To Catch a Thief was based.

Vindication for my teacher! Cool. Thank you very much.

And the title is a pun on Que verde era mi valle, so Dodge was right about the derivation. He just happened to miss the pun.