Which is more correct and/or common "Happy Median" or "Happy Medium"? Any history on the two would also be interesting.
The phrase is happy medium. Here is NOAD's take:
happy medium noun a satisfactory compromise : you have to strike a happy medium between looking like royalty and looking like a housewife.
Happy medium is the "golden mean," Horace's aurea mediocritas.
So apparently it comes to us through classical scholarship.
Medium is a richer concept than
median, and so using the former conveys a more colorful expression.
Where median is a simple quantitative concept (the mid-point in a series of numbers), medium has some philosophical connotations. It literally means (Latin) "the thing in the middle", but it has two overlapping senses which may apply here:
- a conduit, or substance through which other substances move or act (eg, space is the medium of gravity)
- a bridge, something that contains elements of two opposites, that is able to unite them
So happy medium conveys a sense of connection -- harmonious balance -- evoking also (as TimLymington mentioned in a comment) the golden mean of Greek philosophy. The poetry of the phrase gets lost entirely when "median" is substituted.
It is medium, not median.
Here's a dictionary.com link.
The earliest example of the phrase that I've been able to find of that particular phrase is an article in the Perth Magazine of Knowledge and Pleasure, published in 1772. The use of the word "medium" as a bridge between two extremes goes back to the late 16th century.
Median is primarily a mathematical term, but is sometimes confused with medium due to its similar sound and somewhat similar meaning. Interestingly, they also both come from the same Latin root, "medius," which simply meant "middle".
The correct term is "happy median" referring to the middling result of a list of numbers. If the central number, say number 5 out of 9, is skewed higher by 4 more outlying numbers above than below, say for your house value at assessment, then you would have a favorable or "happy" median. It is clearly a statistically-based term, a happy medium being related to a person who channels the dead spirits and enjoys their work or circumstances.
In order to choose between happy median and happy medium one must understand the etymological, formal, and colloquial usages of the two phrases:
Happy medium is a complete phrase in and of itself, while happy median is a partial phrase, shortened from happy median point.
Median, as used in the phrase is not a noun, but an adjective defining an unspoken but understood noun, such as for example a point, place, or locus. (Others are possible, too.)
After the two preceding points are grasped, it is up to the one writing as to which is preferred. Often happy median is considered somewhat more refined, as it requires a rather more erudite knowledge of the English language.