noun (1), often attributive
\ ˈad How to pronounce ad (audio) \

Definition of ad

 (Entry 1 of 7)

1 : advertisement sense 1 newspapers ads TV ads for new cars
2 : advertising an ad agency

Definition of ad (Entry 2 of 7)

Definition of AD (Entry 3 of 7)

1 active duty
2 after date
4 Alzheimer's disease
5 anno Domini often printed in small capitals and often punctuated
6 assembly district
7 assistant director
8 athletic director
9 right ear used especially in audiology and in writing medical prescriptions

Definition of A/D (Entry 4 of 7)



variants: or ac- or af- or ag- or al- or ap- or as- or at-

Definition of ad- (Entry 5 of 7)

1 : to : toward usually ac- before c, k, or qacculturation and af- before faffluent and ag- before gaggradation and al- before lalliteration and ap- before papportion and as- before sassuasive and at- before tattune and ad- before other sounds but sometimes ad- even before one of the listed consonantsadsorb
2 : near : adjacent to in this sense always in the form ad-adrenal


adverb suffix

Definition of -ad (Entry 6 of 7)

: in the direction of : toward cephalad

Definition of -ad (Entry 7 of 7)

: member of a botanical group bromeliad

First Known Use of ad

Noun (1)

1799, in the meaning defined at sense 1

Noun (2)

1915, in the meaning defined above

History and Etymology for ad

Noun (1)

by shortening

Noun (2)

by shortening


borrowed from Latin, prefix forming verbs and verbal derivatives, marking movement toward, tendency, addition, from ad, preposition, "to, as far as, at, near, in accordance with" — more at at entry 1

Adverb suffix

borrowed from Latin ad "to, toward" — more at at entry 1

Noun suffix

borrowed from New Latin -ad-, -as, borrowed from Greek -ad-, -as, feminine noun suffix denoting descent from or connection with

Keep scrolling for more

Learn More about ad

Statistics for ad

Cite this Entry

“Ad.” Dictionary, Merriam-Webster, Accessed 26 Oct. 2020.

Keep scrolling for more

More Definitions for ad


\ ˈad How to pronounce ad (audio) \

Kids Definition of ad

Kids Definition of A.D.

in the year of our Lord
Hint: A.D. is an abbreviation for the Latin phrase anno Domini, which means “in the year of our Lord.”

Medical Definition of AD

3 [Latin auris dextra] right ear used especially in audiology and in writing medical prescriptions
4 average deviation

Keep scrolling for more

More from Merriam-Webster on ad

Thesaurus: All synonyms and antonyms for ad

Nglish: Translation of ad for Spanish Speakers

Britannica English: Translation of ad for Arabic Speakers

Comments on ad

What made you want to look up ad? Please tell us where you read or heard it (including the quote, if possible).


Test Your Vocabulary

Namesakes Word Quiz

  • a citrus fruit possibly named after a person
  • Which of the following is a fruit named after a Moroccan seaport?
Spell It

Can you spell these 10 commonly misspelled words?


Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!