Wordorigins.org

Many people wonder where these two computer terms come from. Of the two, bit is older, dating to 1948. It first appears in A Mathematical Theory of Communication by C.E. Shannon in Bell Systems Technical Journal in July and October of that year. (This paper is one of the seminal works of modern information theory. The fact that it is the first known use of bit is simply a footnote to its scientific importance.) In the paper, Shannon credits a J.W. Tukey with the coinage:

The choice of a logarithmic base corresponds to the choice of a unit for measuring information. If the base 2 is used the resulting units may be called binary digits, or more briefly bits, a word suggested by J. W. Tukey.

As Shannon indicates, bit is an abbreviated form of binary digit, chosen probably because it is also a play on the meaning of the then existing word bit signifying a small part.

The term byte is of less certain origin, but probably was coined by someone at IBM (perhaps a Dr. Werner Buchholz) around 1964. The word byte is a play on bit. The original sense of the term was the amount of data required to represent one character—usually, but not always, eight bits. Over time, the predominant sense shifted to mean eight bits exactly.

The first citation in the Oxford English Dictionary is from an article by Messrs. Blaauw and Brooks in a 1964 issue of the IBM Systems Journal:

An 8-bit unit of information is fundamental to most of the formats [of the System/360]. A consecutive group of n such units constitutes a field of length n. Fixed-length fields of length one, two, four, and eight are termed bytes, halfwords, words, and double words respectively.

Some have suggested that it is an abbreviation for BInary digiT Eight and that the Y was substituted for the I so to prevent typographical confusion with bit. Another suggestion is that it is from BinarY TErm. Neither of these claims is well substantiated and are probably false.

Also playful, but less well known, is the term nybble or nibble, meaning half a byte, or four bits.

(Sources: Oxford English Dictionary, 2nd Edition; Safire’s Quoth the Maven; Carver’s A History of English in Its Own Words)

This term for an important person dates to the 18th century. It’s a reference to the powdered wigs that men wore back then. Rich and important men would have larger, more expensive wigs, hence the term.

Slang etymologist Eric Partridge dates the term to 1731, but provides no citation or context for the usage. This, like many of Partridge’s dates, is suspect. The earliest citation in the Oxford English Dictionary is from a 1781 letter by English politician George Selwyn, who is notable for having served 44 years in the House of Commons without ever once making a speech:

A new point of discussion for the lawyers, for our big wigs, for their Lordships.

Contrary to the bit of internet folklore that is floating about, men did not shave their heads under the wigs (or at least most didn’t) and the wigs were not placed in a loaf of bread and baked in order to clean them. That is simply absurd.

(Source: Oxford English Dictionary, 2nd Edition)

This name for New York City was originally horse-racing slang that made its way into the vernacular. The metaphor is that New York City is a succulent and sweet prize to be had for those who are successful in racing or any field of endeavor.

Big apple was commonly used in the late-19th century to refer to the winnings of a wager. This use appears as early as the August 1847 issue of The American Farmer:

Try it once and we’ll bet you a big apple that you do it every year thereafter for the balance of your life.

This verb ultimately comes from the late-Latin *exlītigāre via the Old French esligier and the Anglo-Norman aligier, meaning to clear at law. One might think that it comes from the Latin allēgāre, which has the same meaning as the modern English word, but this similarity is due to later conflating the two terms. If it came from the latter root, the modern form would be alleague.

The original sense of allege was to make an oath. It appears in the anonymous poem The Pearl, c.1325:

Forþy to corte quen þou schal com
Þer alle oure causeȝ schal be tryed,
Alegge þe ryȝt, þou may be innome,
By þys ilke spech I haue asspyed

(Therefore to court when you shall come
There all our cases shall be tried,
Allege the right. You may be caught out,
By this same speech I have spied.)

The sense meaning to assert without proof, which is the sense most in use today, appears shortly after. From William Langland’s 1377 Piers Plowman (B text):

Þei wol allegen also, quod I, and by þe gospel preuen.
(They will allege also, say I, and by the gospel prove.)

(Source: Oxford English Dictionary, 2nd Edition)

Grant Barrett, over at The Lexicographer’s Rules has an article on what criteria to use when buying a dictionary.

His comment on etymology makes me a bit uncomfortable. Although he’s right that etymology is not an absolute requirement for most everyday uses. If you’re going to invest $30+ for a good dictionary that will last you several years, you should get one with etymologies. Chances are, you will want to look up a word’s origins at some point.

And note that his criteria apply equally well to evaluating online dictionaries.