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How to add a dictionary in iOS 10

shamsigai

October 22, 2026

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If you read Russian-language texts on your iPhone — news articles, e-books, messages from friends — sooner or later you will hit an unfamiliar word and want a quick definition without leaving the app. On old iOS versions (5 and 6) there was a way to install a custom user dictionary for exactly that. iOS 10 took that option away, which confuses a lot of people. The good news: Apple still ships a built-in Russian explanatory dictionary with the system — it is simply switched off by default. Turning it on takes less than a minute, and this guide shows you how.

Why you can’t add a custom dictionary in iOS 10

Let’s clear up the main misunderstanding first. In iOS 5 and 6, users could add their own custom dictionary files to the system. Starting with later releases, Apple removed that capability: iOS 10 does not let you install a third-party or user-made dictionary at all. The only dictionaries available are the ones Apple bundles with the system — but that bundle is quite generous. It includes a Russian explanatory dictionary alongside English, French, German, Spanish and others, all disabled by default. So instead of “adding” a dictionary, you simply switch on the one you need. If you enjoy tailoring iOS to the way you work, you may also like our guide on how to change Safari’s design on iPhone. Apple Support documents the same Dictionary settings for iPhone.

How to enable the Russian dictionary in iOS 10

Because the dictionary is already on your phone, the whole procedure is just a settings toggle plus a download:

1. Open Settings on your iPhone.
2. Go to General, then tap Dictionary.
3. In the list, tap Russian to check it. You can enable any other dictionaries you want at the same time, for example English.
4. Wait a few seconds while iOS downloads the dictionary files (a checkmark appears next to each enabled dictionary when it is ready). Wi-Fi makes this faster.
5. Open any app with text — Safari, Notes, Mail or Messages.
6. Touch and hold a word, then drag the selection handles to highlight exactly the word you want.
7. Tap Define (or Look Up) in the pop-up context menu. The Russian definition appears right there, without leaving the app.

If it still doesn’t work

If the definition lookup does not appear, work through these checks:

• Go back to Settings, then General, then Dictionary and make sure Russian has a checkmark — the dictionary only works after the download finishes.
• Try selecting a word in a different app. Some third-party apps replace the standard context menu, so Define may be missing there while it works in Safari or Notes.
• Make sure the word is actually Russian (or in one of your enabled dictionary languages) — definitions only appear for matching languages.
• Restart the iPhone if the new dictionary does not show up in the context menu right away.

FAQ

Can I install my own dictionary file in iOS 10?

No. User-added custom dictionaries were supported up to iOS 6, and Apple removed the feature in later releases. In iOS 10 you can only switch Apple’s built-in dictionaries on or off — you cannot import a dictionary file of your own. MacRumors covered many such small iOS 10 changes in its tips roundups.

Does the Russian dictionary work offline?

Yes. Once the dictionary files are downloaded (the checkmark in Settings, then General, then Dictionary), lookups work without an internet connection in most apps. Want more hidden system tricks? See our guide on how to quickly open the installed apps list on macOS 26.

Conclusion

You cannot add a custom dictionary to iOS 10 the way you could on iOS 5 or 6 — but you do not need to. Apple’s built-in Russian explanatory dictionary is already waiting on your iPhone, and enabling it in Settings, then General, then Dictionary gives you one-tap definitions of any word in any app. A thirty-second toggle replaces what used to be a manual installation.