noun, plural op·ti·ma [op-tuh-muh] /ˈɒp tə mə/, op·ti·mums.

the best or most favorable point, degree, amount, etc., as of temperature, light, and moisture for the growth or reproduction of an organism.
the greatest degree or best result obtained or obtainable under specific conditions.


most favorable or desirable; best: optimum conditions.

Origin of optimum

1875–80; < Latin: noun use of neuter of optimus best, suppletive superlative of bonus good

Synonyms for optimum

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for optimum

Contemporary Examples of optimum

  • As for the search, which will soon resume, Soelisto confessed that “the capability of our equipment is not optimum.”

    The Daily Beast logo
    Did Bad Weather Bring Down AirAsia 8501?

    Clive Irving

    December 29, 2014

  • One reason for that is filmmakers shot with 16mm lenses on hand-cranked cameras for optimum authenticity.

    The Daily Beast logo
    Who Invented the ‘Teenager’?

    Nina Strochlic

    March 14, 2014

  • Even salt is chemically broken down and rebuilt for optimum flavor.

    The Daily Beast logo
    How Fast Food Hooks Us

    Nina Strochlic

    February 25, 2013

  • I read Anthropometry of Algerian Women and Optimum Handle Height for a Push-Pull Type Manually Operated Dryland Weeder.

    The Daily Beast logo
    The Self-Educated Apple Genius

    James Marcus Bach

    September 13, 2009

  • The last two years was sort of the optimum personal fun, because we were the majority.

    The Daily Beast logo
    Barney Frank Hits Back

    Lloyd Grove

    April 2, 2009

Historical Examples of optimum

  • Nothing is more pleasant than a day of this optimum kind in May or June.

  • Cultivation has been carried far beyond the optimum regions.

    The Apple-Tree

    L. H. Bailey

  • My cousin, young Denny Swinton, was to dine with me that evening at the Optimum.


    Anthony Hope

  • It will be very seldom that a plant is likely to be found at the optimum.

    Life Movements in Plants

    Sir Jagadis Chunder Bose

  • In the present case the optimum temperature is in the neighbourhood of 35C.

    Life Movements in Plants

    Sir Jagadis Chunder Bose

British Dictionary definitions for optimum


noun plural -ma (-mə) or -mums

a condition, degree, amount or compromise that produces the best possible result


most favourable or advantageous; bestoptimum conditions

Word Origin for optimum

C19: from Latin: the best (thing), from optimus best; see optimism
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 optimum

1879, from Latin optimum, neuter singular of optimus "best" (used as a superlative of bonus "good"), probably related to ops "power, resources" (in which case the evolution is from "richest" to "the most esteemed," thus from PIE root *op- "to work") or to ob "in front of," with superlative suffix *-tumos. Originally in biology, in reference to "conditions most favorable" (for growth, etc.). As an adjective from 1885.

Online Etymology Dictionary, © 2010 Douglas Harper