Idiom \ID-ee-uhm\ , noun;
1. An expression whose meaning is not predictable from the usual meanings of its constituent elements or from the general grammatical rules of a language and that is not a constituent of a larger expression of like characteristics
2. A language, dialect, or style of speaking peculiar to a people
3. A construction or expression from one language whose parts correspond to elements in another language but whose total structure or meaning is not matched in the same way in the second language
4. The peculiar character or genius of a language
5. A distinct style or character, in music, art, etc.
Dating to the 1850's, the origin of idiom is Middle French idiome from Late Latin idioma ("a peculiarity in language"). The Latin word comes from Greek idioma ("peculiarity, peculiar phraseology") which derives from idioumai ("I make my own") from idios ("personal, private," literally "particular to oneself"). The Proto-Indo-European forebear is *swed-yo-, which is based on the third person reflexive pronoun *s(w)e-. Confused? "Third person reflexive pronoun" equals "ourselves."
The reason I wanted to talk about idiom today is because of an NPR article yesterday. It gives a brief history of the King James Bible and talks about the poetic nature of the text. The part I found most interesting was the number of idiomatic phrases that are found in the Bible that we still use today. Some are obviously biblical ("forbidden fruit,"fire and brimstone," etc.), but others are more surprising. "Put words in her mouth," "fall by the wayside,""by the skin of your teeth," and "there's nothing new under the sun" are a few I was surprised to see.
At the end of the article they linked to another NPR article about a book by David Crystal, Begat: The King James Bible and the English Language. In it he talks about how a lot of expressions in Modern English (and pop culture) have roots in the King James Bible. I haven't read the book yet, but it's on my reading list!