add up,
    1. to make the desired, expected, or correct total: These figures don't add up right.
    2. to seem reasonable or consistent; be in harmony or accord: Some aspects of the story didn't add up.

Origin of add

1325–75; Middle English adden < Latin addere, equivalent to ad- ad- + -dere to put (combining form; see do1)
Related formsadd·a·ble, add·i·ble, adjectiveadd·ed·ly, adverbmis·add, verbre·add, verb (used with object)un·add·a·ble, adjectiveun·add·ed, adjectiveun·add·i·ble, adjective
Can be confusedad add oddaddable edibleadds ads adz

Synonyms for add Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for add up

add up

verb (adverb)

to find the sum (of)
(intr) to result in a correct total
(intr) informal to make sense
(intr foll by to) to amount to



to combine (two or more numbers or quantities) by addition
(tr foll by to) to increase (a number or quantity) by another number or quantity using addition
(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
(intr foll by to) to have an extra and increased effect (on)her illness added to his worries
(tr) to say or write further
(tr foll by in) to include


informal an instance of adding someone to one's list of contacts on a social networking site, esp MySpaceThanks for the add!
See also add up

Word Origin for add

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


abbreviation for

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

Word Origin and History for add up



late 14c., "to join or unite (something to something else)," from Latin addere "add to, join, attach, place upon," from ad- "to" (see ad-) + -dere comb. form meaning "to put, place," from dare "to give" (see date (n.1)). Meaning "to do sums, do addition" also is from late 14c. Related: Added; adding. To add up "make sense" is from 1942.

Online Etymology Dictionary, © 2010 Douglas Harper

add up in Medicine



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

add up in Science


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

Idioms and Phrases with add up

add up


Amount to an expected or correct total, as in These figures don't add up, meaning they are not correct. [Mid-1800s]


Be consistent, make sense, as in I'm not sure that all this testimony will add up. [First half of 1900s]


Assess, form an opinion of, as in He looked across the track and added up the competition. Also see add up to.

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