[ ad ]
See synonyms for add on
verb (used with object)
  1. to unite or join so as to increase the number, quantity, size, or importance: to add two cups of sugar; to add a postscript to her letter;to add insult to injury.

  2. to find the sum of (often followed by up): Add this column of figures.Add up the grocery bills.

  1. to say or write further.

  2. to include (usually followed by in): Don't forget to add in the tip.

verb (used without object)
  1. to perform the arithmetic operation of addition: children learning to add and subtract.

  2. to be or serve as an addition (usually followed by to): His illness added to the family's troubles.

  1. Journalism. copy added to a completed story.

Verb Phrases
  1. add up to, to signify; indicate: The evidence adds up to a case of murder.

Idioms about add

  1. add up,

    • to make the desired, expected, or correct total: These figures don't add up right.

    • to seem reasonable or consistent; be in harmony or accord: Some aspects of the story didn't add up.

Origin of add

First recorded in 1325–75; Middle English adden, from Latin addere, equivalent to ad- ad- + -dere “to put” (combining form; see do1)

Other words for add

Other words from add

  • add·a·ble, add·i·ble, adjective
  • add·ed·ly, adverb
  • mis·add, verb
  • re·add, verb (used with object)
  • un·add·a·ble, adjective
  • un·add·ed, adjective
  • un·add·i·ble, adjective

Words that may be confused with add

Words Nearby add

Other definitions for ADD (2 of 2)

[ ey-dee-dee ]

abbreviation, noun
  1. attention deficit disorder: the inattentive subtype of ADHD, usually marked by distractibility and difficulties with executive function.

Origin of ADD

First recorded in 1975–80 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use add in a sentence

British Dictionary definitions for add (1 of 2)


/ (æd) /

  1. to combine (two or more numbers or quantities) by addition

  2. (tr foll by to) to increase (a number or quantity) by another number or quantity using addition

  1. (tr often foll by to) to join (something) to something else in order to increase the size, quantity, effect, or scope; unite (with): to add insult to injury

  2. (intr foll by to) to have an extra and increased effect (on): her illness added to his worries

  3. (tr) to say or write further

  4. (tr foll by in) to include

  1. informal an instance of adding someone to one's list of contacts on a social networking site, esp MySpace: Thanks for the add!

Origin of add

C14: from Latin addere, literally: to put to, from ad- to + -dere to put

British Dictionary definitions for ADD (2 of 2)


abbreviation for
  1. attention deficit disorder

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 ADD


  1. Abbreviation of attention deficit disorder

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