A podcast app that explains the words you don't know
Updated September 2026. iPhone, iOS 26 or later.
You are half an hour into an episode and someone says a term you have never heard. You have three bad options: stop the episode and type it into a search box, guess, or let it go and lose the next two minutes wondering.
Unpack is a podcast player built to remove that choice. Ask for the word and it tells you, out loud, while the episode keeps going.
Why a general dictionary gets it wrong
A dictionary does not know what you were listening to. Ask it about "UGC" and it may tell you about Uganda. Ask about "ROI" and you get a list of unrelated entries.
Unpack reads the transcript around the exact second you asked, roughly thirty seconds of it, and answers from that. In a marketing episode, UGC is user generated content. In an economics episode, "tapering" is about central banks, not exercise.
The short version. Unpack knows what the episode is about. That is the whole difference between a definition that helps and a definition that wastes your time.
Three ways to ask
- Siri. Say "Hey Siri, define that in Unpack." It works with the screen off and the phone in your pocket.
- An AirPods head gesture. Shake your head to trigger the lookup, nod to pick a term, and the definition is read to you. Your hands never leave what they were doing. This one is a premium feature.
- The screen. Open the episode, tap a term in the live transcript, read the definition.
After a spoken lookup the player rewinds a few seconds, so you pick the episode back up where your attention left it instead of a sentence later.
Podcasts without transcripts still work
When a show publishes a transcript in its feed, Unpack uses it. When it does not, the app transcribes the audio on your phone using Apple's on-device speech framework. Nothing is uploaded to do it. This is the reason the app needs iOS 26 or later: below that version, an episode without a published transcript would be a dead end.
What happens to the words you look up
Every lookup is saved into a personal glossary, tagged by the subject it came from. That list does more than sit there:
- Terms come back days later as short quizzes, spaced out so they stick.
- The app learns which words you already know and stops offering them.
- In the live transcript it can mark the terms it expects you not to know, before you ask.
- A monthly summary shows how many terms you learned and which subjects you are strongest in.
It is still a proper podcast player
Subscribe by RSS or import everything at once from an OPML file exported by Overcast, Pocket Casts, Castro or Apple Podcasts. Playback speed, skip forward and back, downloads for offline, a sleep timer, background audio, lock screen controls, and a Live Activity in the Dynamic Island.
Where your data goes
Definitions are produced on the device first, by Apple's on-device model. Nothing leaves the phone in that path. Only when the on-device model cannot answer does a short transcript excerpt go to a Claude proxy, and Settings has a switch that turns that off for good. Your glossary and listening history stay on the device.
Honest limits
- iPhone only. No iPad, Mac, Apple Watch or CarPlay version.
- iOS 26 or later. This is a hard requirement, not a preference.
- The app interface is in English. Definitions, transcription and spoken readback follow the podcast's own language for English, Spanish, German and French.
- Free accounts get ten lookups a day and one review quiz session a day. The player, downloads, Siri and the glossary itself are not limited.
- The AirPods head gesture, live transcript highlighting and comprehension quizzes during playback are premium.
Questions people ask
Does the episode stop while it defines a word?
No. That is the point. The audio keeps playing, or ducks briefly for a spoken answer, then rewinds a few seconds so you do not lose the thread.
Is this an app for learning English?
Not specifically. It is for anyone listening to a podcast outside their own field: a designer listening to an economics show, an engineer listening to a medical one. It works the same way for a non-native speaker, but the terms it explains are jargon and named entities, not everyday vocabulary.
Do I need a subscription to get good definitions?
No. Definition quality is not held back for paying users. Free and premium get the same context-aware answer. Premium removes the daily count and unlocks the hands-free and highlighting features on top.
Can I use my existing subscriptions?
Yes. Export an OPML file from the app you use now and import it on the first run. Every major podcast app can produce one.
Free to download. Ten lookups a day at no cost.
Overcast, Pocket Casts, Castro and Apple Podcasts are trademarks of their respective owners. Unpack is not affiliated with any of them.