[ ran-duhm ]
See synonyms for: randomrandomlyrandomness on Thesaurus.com

  1. proceeding, made, or occurring without definite aim, reason, or pattern: the random selection of numbers.

  2. Statistics. of or characterizing a process of selection in which each item of a set has an equal probability of being chosen.

  1. Building Trades.

    • (of building materials) lacking uniformity of dimensions: random shingles.

    • (of ashlar) laid without continuous courses.

    • constructed or applied without regularity: random bond.

  2. Slang.

    • unknown, unidentified, or suspiciously out of place: A couple of random guys showed up at the party.

    • odd or unpredictable, often in an amusing way: my totally random life.

  1. something that is random, or a random state or condition: different statistical methods used to estimate randoms.

  2. Slang.

    • a person or thing that is unknown, unidentified, or suspiciously out of place.

    • a person or thing that is odd or unpredictable.

  1. Chiefly British. bank3 (def. 7b).

  1. Building Trades. without uniformity: random-sized slates.

Idioms about random

  1. at random, without definite aim, purpose, method, or adherence to a prior arrangement; in a haphazard way: Contestants were chosen at random from the studio audience.

Origin of random

First recorded in 1275–1325; Middle English raundon, random, from Old French randon, derivative of randir “to gallop,” from Germanic

Other words for random

Other words from random

  • ran·dom·ly, adverb
  • ran·dom·ness, noun
  • non·ran·dom, adjective
  • non·ran·dom·ness, noun

Words Nearby random

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use random in a sentence

British Dictionary definitions for random


/ (ˈrændəm) /

  1. lacking any definite plan or prearranged order; haphazard: a random selection

  2. statistics

    • having a value which cannot be determined but only described probabilistically: a random variable

    • chosen without regard to any characteristics of the individual members of the population so that each has an equal chance of being selected: random sampling

  1. informal (of a person) unknown: some random guy waiting for a bus

  1. at random in a purposeless fashion; not following any prearranged order

Origin of random

C14: from Old French randon, from randir to gallop, of Germanic origin; compare Old High German rinnan to run

Derived forms of random

  • randomly, adverb
  • randomness, noun

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

Scientific definitions for random


[ răndəm ]

  1. Relating to a type of circumstance or event that is described by a probability distribution.

  2. Relating to an event in which all outcomes are equally likely, as in the testing of a blood sample for the presence of a substance.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Other Idioms and Phrases with random


see at random.

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.