ASO glossary: the terms, in one sentence each

App Store Optimization (ASO) is the work of making an app easier to find and more convincing to download on the App Store and Google Play.

It has two halves: keywords, so the app appears for the searches people make, and conversion, so the people who see it download it. Both are measured over time, which is why ASO tools track rankings and downloads every day.

See the guide: What is App Store Optimization (ASO)?

Conversion rate is the share of people who download an app after seeing it in the store, as a percentage.

App Store Connect divides downloads by the unique devices that saw the app in search results, browsing or on its product page. It moves with the icon, screenshots, rating and how relevant the app is to the search it appeared for.

See the guide: App Store conversion rate: what it is and how to improve it

Difficulty is a 0–100 estimate of how hard it is to rank in the top results for a keyword, based on how established the apps already ranking there are.

Neither Apple nor Google publishes it, so every ASO tool estimates it. Use it to compare keywords with each other, not as a promise: a low score means the top 10 is beatable, not that you will beat it.

See the guide: How to do App Store keyword research

An extra localization is a second language that an App Store storefront indexes besides its main one, giving the same app another title, subtitle and keyword field to rank from in that country.

The United States storefront, for example, is widely observed to index Spanish (Mexico) as well as English. Apple does not document the mapping, so treat the extra fields as room for additional keywords and track whether they rank.

See the guide: How to localize App Store keywords for other countries

An impression is one time an app is shown in the store, in a list of search results, on a chart or on its own product page.

App Store Connect reports impressions by source and country. Conversion rate divides downloads by the unique devices behind those impressions, so a keyword that gains rank usually shows up first as more impressions from search.

See the guide: App Store conversion rate: what it is and how to improve it

The keyword field is the hidden, 100-character list of comma-separated keywords an App Store app is indexed for in addition to its name and subtitle.

Only the developer sees it, in App Store Connect. Words in it combine with the name and subtitle to form the searches the app can appear for, so it should hold the words those two fields do not already use. Google Play has no keyword field.

See the guide: How to use the App Store keyword field

A keyword rank is an app’s position in the store’s search results for one search, in one storefront, on one day.

The App Store returns up to 200 results for a search and Google Play 30, so ranks are read to those depths; an app below them shows as unranked. Ranks differ by country and move daily, which is why they are tracked rather than checked once.

See the guide: How to track App Store keyword rankings

A localization is one language version of an app’s store listing: its own name, subtitle, keyword field, description and screenshots.

Each storefront indexes one or more localizations. Keywords do not combine across them, so every localization is scored on its own, and a localization you have not set up is empty room rather than a copy of the main one.

See the guide: How to localize App Store keywords for other countries

Popularity is a 0–100 estimate of how often a keyword is searched in a store, relative to other keywords in that store.

Neither Apple nor Google publishes search volume. Apple does publish popularity scores for its weekly top search terms through Apple Ads; for every other keyword the number is an estimate blended from autocomplete signals and the size of the results.

See the guide: App Store keyword search volume: how to check popularity

A pressure test is a check of a metadata draft against the store’s rules and against the keywords the app ranks for today, run before the draft is published.

It lists what would be rejected, what quietly costs rankings, such as a keyword the new text no longer covers, and what passes. In asorocket it is part of the Metadata lab.

See the guide: ASO checklist: what to check before you submit an App Store update

A product page view is one time an app’s full store page is opened, as opposed to an impression, where the app was only shown in a list.

The ratio of product page views to impressions says whether the icon, name and subtitle earn a tap; the ratio of downloads to page views says whether the screenshots, description and rating earn the download.

See the guide: App Store conversion rate: what it is and how to improve it

A search visibility score is a single 0–100 number that sums up how visible an app is for a set of tracked keywords in one country, weighting each keyword by its popularity and scoring it by rank.

It turns dozens of daily rank moves into one line you can watch. In asorocket, competitors are scored on the same keywords, so their lines compare directly with yours.

See the guide: How to track App Store keyword rankings

A storefront is the App Store of one country or region, with its own search results, charts, prices and indexed languages.

There are 175 App Store storefronts. An app ranks separately in each, so a keyword is tracked per storefront, and Google Play likewise returns different results per country.

See the guide: How to localize App Store keywords for other countries

A top chart is a store’s ranked list of the most downloaded or highest-grossing apps, overall or in one category, in one country.

The App Store has Top Free, Top Paid and Top Grossing charts; Google Play has its own. A chart position is a second kind of rank next to keyword ranks, and competitor tracking records both every day.

See the guide: How to analyze competitors on the App Store