See synonyms for j on Thesaurus.com
  1. Mathematics. a unit vector on the y-axis of a coordinate system.

  2. Engineering. the imaginary number .

Words Nearby j

Other definitions for J (2 of 5)


or j

[ jey ]

noun,plural J's or Js, j's or js.
  1. the tenth letter of the English alphabet, a consonant.

  2. any spoken sound represented by the letter J or j, as in just, major, or rajah.

  1. something having the shape of a J.

  2. a written or printed representation of the letter J or j.

  3. a device, as a printer's type, for reproducing the letter J or j.

Other definitions for J (3 of 5)


  1. Physics. joule; joules.: Also j

Other definitions for J (4 of 5)


  1. the tenth in order or in a series.

  2. (sometimes lowercase) the medieval Roman numeral for 1.: Compare Roman numerals.

Other definitions for J. (5 of 5)


  1. Cards. Jack.

  2. Journal.

  1. Judge.

  2. Justice.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use j in a sentence

British Dictionary definitions for j (1 of 3)


symbol for
  1. maths the unit vector along the y -axis

  2. Also called: i obsolete the imaginary number √–1

British Dictionary definitions for j (2 of 3)



/ (dʒeɪ) /

nounplural j's, J's or Js
  1. the tenth letter and seventh consonant of the modern English alphabet

  2. a speech sound represented by this letter, in English usually a voiced palato-alveolar affricate, as in jam

British Dictionary definitions for J (3 of 3)


symbol for
  1. cards jack

  2. joule(s)

  1. current density

abbreviation for
  1. Japan (international car registration)

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 J


  1. Abbreviation of joule

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