Happy medium or happy median

the pic has no relation to what i want to write today...hehehe

A fellow asked if the usual and correct phrase is happy medium or happy median.

Happily enough, that's an easy question to answer. One early (and very old) sense of the word medium (which comes from the Latin medius meaning "middle") is "the middle way"; "compromise." A happy medium is a compromise that satisfies.

Median, meanwhile, which also counts that Latin medius as an ancestor, indicates a midpoint in position. When median isn't being used as shorthand for "median strip," it is used chiefly to indicate the point below which there are as many instances as there are above. For example, if the costs of five different lunches are $2, $2, $4, $20 and $25, the median meal costs $4.

Got that? Now let's look at a term whose meanings run the gamut: compromise. When compromise first appeared back in the 15th century, that term named "an agreement to refer matters in dispute to arbitrators." Compromise has an ancestor in a Middle English term meaning "mutual promise (from Latin com plus promittere) to abide by an arbiter's decision."

While a compromise can sometimes name a "happy medium"—the settlement of differences by consent reached by mutual concessions—it can also mean "a concession to something derogatory or prejudicial," such as a compromise of principles.