The entire 2,074 page, 7.5 pound dictionary with its nearly 300,000 terms –plus 64 thousand recorded sound files all available instantly at your fingertips.


"In battle of the Big Three dictionaries, American Heritage® stands out on iPhone" (4 mice)
— MacWorld

This iPhone/iPod touch version has the entire 2,074 page, 7.5 pound dictionary with its nearly 300,000 terms –plus 64 thousand recorded sound files by native speakers– all available instantly at your fingertips.
More than 33,000 written examples, totaling 4,222,000 words, makes this largest mobile dictionary on ANY platform
The indexes alone are larger than most brand-name dictionaries. Even without the sound files, AHD4 would still be over 100MB and the largest dictionary in the AppStore.

Main Features:
● entire text of this best selling book
● complete front matter and appendicies
● three-way cross-referencing search
● real-time progressive look-up
● wildcard pattern searches (with * ?)
● spelling suggestion dictionary included
● internal hyperlinking & supports copy/paste
● pop-up pronunciation symbols chart
● IPA pronunciation symbol conversion
● etymology (word history) with root links
● professionally recorded sound files
● zoomable graphics
● unique two-way external application interaction
— first iPhone dictionary with external linking and now most advanced!
● 3D Touch support
● DarkMode support
● iPad Pro multi-screen and Drag & Drop
● iPhone X & 11 support
● bookmarks with editable notations
● automatic search history
● complete offline use - no Internet connection

The renowned American Heritage® Usage Panel, a group of more than 200 distinguished writers, scholars, and scientists, offers advice on problems of grammar and style; engaging notes explain word histories and clarify differences among synonyms; thousands of quotations and example sentences show words in context; and elegant definitions are enhanced by numerous full-color photographs, drawings, and maps, making this one of the most complete reference tool available on any mobile platform.

Reviews for the application:

"As apps go, only Enfour’s American Heritage® Dictionary stands out for its graphic appeal and functionality. Although I was pleased to have so much lexical firepower in such a compact form, I was annoyed at how poorly the other dictionaries present on the platform." (4 mice)
— MacWorld

Editor's Choice. ranking = "Great"
— MacLife

Reviews of the print version:

"The Best Dictionary...Designed to appeal to the eye as well as the mind, it is notable for its imaginative illustrations....This is a great family dictionary, and ideal for schoolrooms."
— The Courier Journal

"This dictionary, now in its fourth edition, makes it fun to look up definitions of words....This up-to-date and eminently useful dictionary features a fabulous full-color design that quickly and effectively guides users to the information they seek."
— Library Journal


The American Heritage® Dictionary of the English Language, Fourth Edition published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


Powered by Enfour's "UniDict® Engine"

—lookup definitions from "SpellChecker"

—thesaurus links work with these products:
"Roget's II: New Thesaurus"
"Companion Thesaurus"
"Companion Synonyms"

What’s New

Version 9.4

Adds a multi-level "Back" button.
Adds Roget's II Thesaurus via in-app purchase.

Ratings and Reviews

3.6 out of 5
7 Ratings

7 Ratings

bill.j ,

Great dictionary, a few bugs, tech support possibly lacking

Originally purchased the American Heritage Desk Dictionary, which is very nice. Then discovered the Fourth Edition. The AHD Fourth Edition has many more words than the Desk version, plus it "speaks" pronunciations. However, very often, when I look up a word, I get a blank screen, and have to toggle between text sizes to make the dictionary entry appear. Typing a query in the search field, especially the first time after I launch the dictionary, is annoyingly sluggish. Finally, I'm disappointed that, after reporting these issues to the developer (via the email address obtained from their Web site), I never received a reply. I hope the developers will read this posting, and address the glitches I've described. At that point, the product will be worthy of a 5-star rating. It's great to be able to carry full-fledged version of a premium dictionary in my pocket! This is one of the more costly iPhone apps, but in my opinion, worth the expense. (It's also rather large. I just hope it's not TOO large for the iPhone to handle, and that the issues I've experienced are not an unresolvable consequence of its size.)

WaltGom ,

Great Dictionary

But every time I try to use it, it puts up a pop up box to get me to rate it five stars.

thehappycamper ,

Almost Perfect

-- The dictionary itself is incredibly comprehensive. The definitions are clear, concise, and to the point. There's simply no comparison between this dictionary and the free dictionaries based on WordNet.
-- All words have recorded pronounciation. Written pronounciation is of course also available, with the latest update including a pronounciation key.

User Interface:
-- Search is very fast, loading full and partial matches as you type
-- The History feature is great, letting you view all the words you previously looked up. You can also delete unwanted words from the history.
-- In Search mode, the 'X' button for clearing the search field didn't work very well. This seems to have been fixed in the latest update.
-- Also starting with the latest update, all words are hyperlinked, so you can click on any word in a definition to jump to that word's definition

Minor Annoyances:
-- In Search mode, the 'Info' button is near the 'X' button (including in the latest update). Sometimes the 'Info' button gets pressed by mistake.
-- Sometimes the selected definition doesn't get loaded, instead getting a blank screen. You then have to go back and choose the word again. This may have been fixed in the latest update; I haven't used it long enough to find out.

Apart from that, it's really all I could wish for in a dictionary. Well worth the price in my opinion.


Enfour, Inc.
587.3 MB

Requires iOS 8.0 or later. Compatible with iPhone, iPad, and iPod touch.


English, Arabic, Bosnian, Catalan, Danish, Dutch, Finnish, French, German, Hebrew, Hindi, Hungarian, Indonesian, Irish, Italian, Japanese, Korean, Kurdish, Lithuanian, Malay, Persian, Polish, Portuguese, Russian, Simplified Chinese, Slovenian, Spanish, Swedish, Tagalog, Thai, Traditional Chinese, Turkish, Vietnamese

Age Rating
Infrequent/Mild Profanity or Crude Humor
In-App Purchases
  1. Roget's II Thesaurus $3.99


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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