Demi-,semi-,hemi- Usage with words

Solution 1:

Google found the following: "prefixes-semi-hemi-and-demi":

Orion Montoya, "A trifle bombastic." Lexicographer/Engineer Updated Mar 12, 2011

Hemi- is Greek; Semi- is Latin; Demi- is French. They all mean some kind of "half."

Normally when you form a new word, you're supposed to try to make all of its parts come from the same language: some pedants complain about "television" combining Greek "tele" and Latin "vision." This is not a hard and fast rule but it's the easiest* way to decide which to use, and the majority of the time it explains why one is used over another.

• "Easiest" provided you know the origin of the other parts of the word.

Many demi- words are from the time when English was getting new lexical inventory from the Normans or when French was the lingua franca. So words in heraldry, costume/fashion, arms & armor, and arts in general are likely to use demi-. I feel that forming a new or nonce word today with "demi-" is often meant to exploit this French association in one way or another (to connote fanciness or pretentiousness).

Semi- is often used on technical terms in any subject area, including music and arts and also math. Since much of technical/scientific neologism is Latinate by default, this usually works out. I intuitively feel that "semi-" is the most neutral of the three prefixes in English.

Since hemi- usually comes with Greek roots, it usually seems the most foreign, technical and scientific. Many of its applications are medical, biological, chemical or mathematic. Using hemi- for a casual word formation would likely be a bit humorous.

French itself has a prefix "mi-", which is short for "demi-" but could of course be short for any of them. You can have foie gras mi-cuit, or cheveux mi-longs. Using mi- in English would just be confusing unless you hang out with just the right kind of eurotrash.

OS X's /usr/share/dict/words list contains 951 semi- words, 215 hemi- and 172 demi-. So semi- is by far the most common.