hundred (adj., n.)

"reckoning by twelves and powers of twelve," 1714, from Latin in duodecimo (folded) "in a twelfth" of a sheet, from ablative of duodecimus "twelfth" (from duodecim "twelve;" see dozen) + -al (1).

Divisions based on decimals are convenient for arithmetical calculation and computation of numbers. Duodecimal reckoning was better suited to practical use in weights and measures for material substances (food, drink), as 12 is cleanly divisible by 2, 3, 4, and 6.

In Old Norse hundrath meant 120, that is the long hundred of six score, and at a later date, when both the six-score hundred and the five-score hundred were in use, the old or long hundred was styled hundrath tolf-roett ... meaning "duodecimal hundred," and the new or short hundred was called hundrath ti-rætt, meaning "decimal hundred." "The Long Hundred and its use in England" was discussed by Mr W.H. Stevenson, in 1889, in the Archæological Review (iv. 313-27), where he stated that amongst the Teutons, who longest preserved their native customs unimpaired by the influence of Latin Christianity, the hundred was generally the six-score hundred. The short hundred was introduced among the Northmen in the train of Christianity. [Transactions of the Lancashire and Cheshire Antiquarian Society, 1907]

late 14c., "one hundred," from Latin centum "hundred" (see hundred). The meaning shifted 17c. to "hundredth part" under influence of percent. It was chosen in this sense April 18, 1786, in a Board of Treasury report, as a name for a U.S. currency unit (the hundredth part of a dollar) by the Continental Congress. Dime also first appears as a U.S. coin name in the same document.

The word cent first had been suggested by Robert Morris in 1782 under his original plan for a U.S. currency. Morris's system had an unnamed basic unit at a very small value, and 100 of these was to equal a cent. But the ratio of this cent to the dollar would have been about 144:1.

The Money Unit will be equal to a quarter of a Grain of fine Silver in coined Money. Proceeding thence in a decimal Ratio one hundred would be the lowest Silver Coin and might be called a Cent. [Jan. 15, 1782, Morris's report, included in the Financier's response to a resolution of the Continental Congress on currency exchange]

Thomas Jefferson's counterproposal, which won approval, built on Morris's but eliminated the basic unit and made the decimal system uniform throughout.

Before the cent, Revolutionary and colonial dollars were reckoned in ninetieths, based on the exchange rate of Pennsylvania money and Spanish coin.