Did you know?

Click any word in a definition or example to find the entry for that word

deep - definition and synonyms

What are red words?

90% of the time, speakers of English use just 7,500 words in speech and writing. These words appear in red, and are graded with stars. One-star words are frequent, two-star words are more frequent, and three-star words are the most frequent.

Thesaurus diagram

The thesaurus of synonyms and related words is fully integrated into the dictionary. Click on the thesaurus category heading under the button in an entry to see the synonyms and related words for that meaning.

adverb     deep pronunciation in American English
Word Forms
  1. 1
    a long way into something

    They continued deep into the forest.

  2. 2
    a long way down from the top or the surface

    men who work deep under the ground

    deep below the ocean’s surface

  3. 3
    if people or things are two deep, three deep, etc., there are two, three, etc. rows of them behind or on top of each other

    People were standing three deep at the side of the road to watch the parade.


deep learning

a form of machine learning which incorporates the use of neural networks

BuzzWord Article

Open Dictionary

snap election

a general election … that is called earlier than expected

add a word


A must for anyone with an interest in the changing face of language. The Macmillan Dictionary blog explores English as it is spoken around the world today.

global English and language change from our blog
Macmillan learn live love play