GA4 without the mystery: an interactive glossary of the terms that matter

By Manáry | September 21, 2026

Anyone coming from the old Universal Analytics found GA4 strange: metrics were renamed, bounce rate got a new definition and page views became events. This glossary brings together the terms that come up most in reports and meetings, explained without jargon.

Glossary

Google Analytics 4 terms

Type to filter. The search ignores accents.

Search term

Event: Any recorded interaction: page view, click, scroll, form submission, purchase. In GA4, every measurement is an event.
Event parameter: Extra information sent with the event, such as purchase value, currency or product name.
Key event: An event marked as important for the business, such as a purchase or lead. Until 2024 GA4 called these events “conversions”; the term conversion is now used in Google Ads.
Enhanced measurement: Automatic collection of common events — scrolls, outbound clicks, site search, file downloads, YouTube videos and form interactions — enabled in the data stream.
Data stream: A data source within a GA4 property: a website, an iOS app or an Android app.
Active user: The default user metric in GA4 reports: people who interacted with the site or app in the period.
Session: A continuous period of interaction by a user. By default, it ends after 30 minutes of inactivity.
Engaged session: A session that lasted more than 10 seconds, had a key event or had at least two page or screen views.
Engagement rate: Engaged sessions as a percentage of total sessions.
Bounce rate: In GA4, the percentage of sessions that weren’t engaged — the inverse of engagement rate. It differs from the Universal Analytics definition.
Engagement time: Time the page or app was in the foreground on the user’s screen.
Source and medium: Where the visit came from (source, such as google or newsletter) and what kind it was (medium, such as organic, cpc or email). They come from UTMs or are detected automatically.
Default channel group: Automatic classification of traffic into channels such as Organic Search, Paid Search, Organic Social, Email and Direct, based on source and medium rules.
Attribution: The rule that splits credit for a key event among the channels the user touched. The default model in GA4 reports is data-driven.
Conversion window: The lookback period in which a touchpoint can receive credit. In GA4, the default is 30 days for acquisition events and 90 days for other key events.
Dimension: An attribute that describes data, such as city, page, device or channel.
Metric: A number that measures something, such as users, sessions, revenue or engagement rate.
Audience: A group of users defined by rules, which can be analyzed in reports and shared with Google Ads for remarketing.
Explorations: GA4’s advanced analysis area, with formats such as free form, funnel and path.
Data retention: How long user- and event-level data stays available in Explorations: 2 months by default, extendable to 14 months in the free version.
Consent mode: A Google feature that adjusts tag behavior according to the visitor’s cookie consent.
BigQuery export: Sending raw event data to BigQuery, also available in the free version of GA4, for analysis without the interface’s limitations.
Measurement Protocol: A way to send events to GA4 from a server — useful for recording sales confirmed outside the site.
User-ID: Your own identifier for logged-in users, which helps join up the same person’s journey across devices.

The three terms that cause the most confusion

Why did my bounce rate change so much?

In Universal Analytics, a bounce was a single-page session. In GA4, it’s a non-engaged session. Someone who spent 3 minutes reading a single article used to count as a bounce and now counts as an engaged session.

Users or active users: which should I use?

GA4’s default reports use active users. To compare periods and channels, always stick to the same metric.

Are a key event and a Google Ads conversion the same thing?

Not necessarily. The key event is set up in GA4; the Google Ads conversion can be imported from GA4 or measured by Google Ads’ own tag — and each tool attributes credit its own way.

The GA4 reports that matter most for sellers

GA4 reports and the questions they answer
Report	Question it answers	Where to find it
Traffic acquisition	Which channels did sessions and key events come from?	Reports › Acquisition
User acquisition	Which channel did each user first arrive through?	Reports › Acquisition
Pages and screens	Which pages get the most visits and engagement?	Reports › Engagement
Events	Which interactions happen and how often?	Reports › Engagement
Attribution model comparison	How does conversion credit change between models?	Advertising › Attribution

How to set up key events without mistakes

List the business actions
Purchase, proposal form submission, click to WhatsApp, material sign-up. Only what really matters becomes a key event.
Create the events in Tag Manager
With specific triggers, such as the confirmed form submission, not just a page load.
Validate in DebugView
Take the action on the site and check the event arrives exactly once, with the right parameters.
Mark it as a key event
In the GA4 panel, under Admin, mark the event as key.
Import into Google Ads carefully
Avoid having the same conversion counted by the Google Ads tag and the GA4 import at the same time as a primary action.

Settings every GA4 should have

data retention extended to 14 months in the property settings;
internal traffic filters so your own team’s visits aren’t counted;
links to Google Ads and Search Console;
an unwanted referrals list, such as payment gateways that “steal” the sale’s source;
a documented UTM standard for every campaign outside Google.

These settings are part of the implementation and validation in Manáry’s Data & Analytics onboarding.

Frequently asked questions

What changed from Universal Analytics to GA4?

GA4 measures everything as events, replaced the old bounce rate with the concept of engaged sessions, uses data-driven attribution by default and puts more weight on privacy and modeling.

What is a key event in GA4?

It’s an event marked as important for the business, such as a purchase or form submission. Until 2024, GA4 called these events conversions.

How long does GA4 keep data?

Standard reports keep aggregated data; in Explorations, user- and event-level data is available for 2 months by default, extendable to 14 months in the free version.

Is GA4 free?

Yes. There’s a paid version, Google Analytics 360, aimed at companies with very large data volumes and specific support needs.

Do your reports show what the business needs?

We audit GA4 event by event and build the dashboard that answers leadership’s questions.

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Want to apply this to your business?

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