a combining form meaning “tenth,” used in words denoting units of the metric system (deciliter); on this model, extended to other systems (decibel).

Nearby words

  1. decern,
  2. decertify,
  3. decession,
  4. dechlorinate,
  5. decholesterolization,
  6. deciare,
  7. decibar,
  8. decibel,
  9. decidable,
  10. decide

Compare deca-.

Origin of deci-

< French déci- < Latin decimus tenth Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for deci-



denoting one tenth; 10 –1decimetre Symbol: d

Word Origin for deci-

from French déci-, from Latin decimus tenth

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for deci-


in the metric system, word-forming element denoting weights of one-tenth of the standard unit of measure, 1801, from French deci-, taken arbitrarily from Latin decimus "tenth," from decem "ten" (see ten).

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for deci-



One tenth (10-1):decibel.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for deci-


A prefix that means “one tenth,” as in deciliter, one tenth of a liter.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.