The entire 2,074 page, 7.5 pound dictionary with its nearly 300,000 terms –plus 64 thousand recorded sound files & "Roget's II: The New Thesaurus".

• The American Heritage® Dictionary of the English Language
• Roget's II: The New Thesaurus


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

Includes all the functionality of these two titles in one application.

This iPhone/iPod touch version has the entire 2,074 page, 7.5 pound dictionary with its nearly 300,000 terms more than 33,000 written examples –plus 64 thousand professionally recorded sound files. Not to mention the complete front matter and appendices, zoomable graphics -all available instantly at your fingertips.
This makes for the largest English dictionary & thesaurus set on ANY mobile platform.

Main Features:
• entire text of these best selling tomes
• complete front matter and appendices
• unique three-way cross-referencing search
• real-time progressive look-up
• wildcard pattern searches (with * ?)
• spelling suggestion dictionary included
• hyperlinking to appendices and between books
• pop-up pronunciation symbols chart
• IPA symbol conversion
• etymology (word history) with root links
• professionally recorded sound files
• zoomable graphics
• support for search from other applications
• Bookmarks with folders & editable notations
• automatic search History
• "Share" module to search within other apps
 - with a history feature, so you can study later
• "Word-of-the-Day" feature with multiple words sets
• 3D Touch support
• DarkMode support
• iPad Pro multi-screen and Drag & Drop
• iPad "Fast App Switching" (Multitasking)
• iPhone 12 & iOS14 support
• OS-independent app localization
• complete offline use — no Internet connection


"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" and "Roget’s II: The New Thesaurus, Third Edition" are published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Houghton Mifflin Harcourt Publishing Company

Powered by Enfour's -"UniDict® Engine 10"

What’s New

Version 10.0.5

Fixes SlideOver on iPad Pro 11-inch and more.

Ratings and Reviews

4.7 out of 5
3 Ratings

3 Ratings

swtbby ,

My go to Dictionary.

A few years back the developers had made a decision to stop supporting and updating this app, meaning eventually an update to the iSO would kill it. I don’t know how many people pushed back, I know I did. Hats off and thanks to the developers for re-thinking that decision.

Developer Response ,

We never stopped supporting it. Updates were slow for a while -due to issues beyond our control. They are coming thick and fast now.

Conrad Halling ,

An Invaluable Resource

As a person who once owned the dead tree version of this dictionary, I am still amazed that I can carry around an unabridged dictionary on my iPhone and iPad. I use this app multiple times a day.

Bifocal Man ,

Wow! Wish I Had Purchased This First

I saw the reviews on sound not working for some downloads. The sound works on every word I've tried so far, and I've sampled a few dozen words. This is the best dictionary/thesaurus I have owned since I took my original printed American Heritage dictionary to college in 1973.

I purchased Rogets II first, then an under $20 combo dictionary thesaurus, and a cheaper dictionary. They fell short because only the common words were in these. I needed more depth. I decided to take a chance on this combo before many reviews were in, and I am glad I did. There are words in here that the cheaper dictionaries don't offer--a lot of them. It is very convenient to have the thesaurus in the same app so that you don't have to leave one to go to the other. I write for a living, and I plan to use this great resource extensively. The larger type size helps me and my bifocals. Thanks.

If you download this on your iPhone, as I did, be patient because it take about 8 to 10 minutes. I had to keep my iPhone awake by sliding my finger over the screen several times during the download. When the blue bar stops, it will keep installing, so just let it continue. A reviewer on the stand-alone dictionary recommends buying through your desktop/laptop with iTunes because of the size. Live dangerously, use your iPhone, but be patient.

App Privacy

The developer, Enfour, Inc., indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer's privacy policy.

Data Not Linked to You

The following data may be collected but it is not linked to your identity:

  • Location
  • User Content
  • Identifiers
  • Usage Data
  • Diagnostics

Privacy practices may vary, for example, based on the features you use or your age. Learn More


Enfour, Inc.
609.5 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


  • Family Sharing

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

More By This Developer

You May Also Like