Q: Just now, the chairman of the board of a financial institution with several hundred billion dollars of assets under management used “dimunition” where he meant “diminution.” I don’t often hear either word, but I hear “dimunition” about as often as “diminution.” Do you OK this usage?
A: No, we don’t recommend using “dimunition” to mean a decrease or the act of decreasing. Although Google searches indicate that thousands of people use “dimunition” that way, many thousands more prefer “diminution.”
More important, we haven’t found “dimunition” in a single standard dictionary, either as an entry or as a variant of “diminution,” the accepted spelling of the word.
Although the spelling of “diminution” has varied a bit since it entered English in the 1300s, none of the forms have included “dimunition” or something pronounced like it, according to the Oxford English Dictionary.
English borrowed the word from the Anglo-Norman term diminuciun, but the ultimate source is deminutio, classical Latin for a decrease.
The earliest example in the OED is from Chaucer’s Middle English poem Troilus and Criseyde (circa 1374): “To encrece or maken dyminucioun / Of my langage.”
Here’s an example, with the modern spelling, from an article by Joseph Addison in the Sept. 23, 1712, issue of the Spectator: “I shall give my reader a Copy of his Letter, without any Alteration or Diminution.”
The usage you’ve noted seems to be relatively new. The earliest example we could find in a search of Google Books was from Communicating Ideas: The Politics of Scholarly Publishing (1991), by Irving Louis Horowitz:
“Less speculative is that the new information technology represents not a dimunition but an addition to what now exists in the way of publishing potential.”
For what it’s worth, most of the early examples were from academic, scientific, or political writing. And, no, we didn’t find a military example of “dimunition” in the sense of a weapon with a double whammy.