GA4 & GTM glossary

Google's current analytics platform, built on an event-based data model that replaced the session-based Universal Analytics. Every interaction is an event.

The container for a single site or product's data in GA4. It sits below the account and above data streams.

The source of data feeding a GA4 property: a website, an Android app or an iOS app. A web stream generates your Measurement ID.

The G-XXXXXXXXXX identifier for a GA4 web data stream, used to send data from your site to GA4.

A GA4 setting that automatically tracks common interactions (scrolls, outbound clicks, site search, video, file downloads) without extra code.

An optional GA4 feature that uses data from signed-in Google users for cross-device reporting and demographics, at the cost of possible reporting thresholds.

Rules that bucket traffic into channels (Organic Search, Paid Social, Direct and so on) based on the source and medium of each session.

When GA4 estimates results from a subset of your data instead of the full dataset, which can happen on large or complex queries.

A GA4 report that shows events from a single device in real time, used to validate tracking during setup and QA.

Any tracked interaction in GA4: a page view, click, form submission or purchase. GA4's entire model is built on events and their parameters.

GA4's term for a conversion: an event you mark as a meaningful business outcome, such as a purchase or a qualified lead.

The percentage of sessions or users that complete a key event. GA4 reports both a session and a user conversion rate.

A registered event or user parameter (such as plan type or author) that lets you segment reports by attributes specific to your business.

A registered numeric parameter (such as a quote value) that you can report on as a metric in GA4.

A group of users defined by behaviour or attributes, used for analysis and, when linked to Google Ads, for remarketing.

The share of sessions that were engaged (lasted over 10 seconds, had a key event, or had two or more page views). GA4 reports this instead of leaning on bounce rate.

In GA4, the inverse of engagement rate: the percentage of sessions that were not engaged. It is calculated differently from Universal Analytics.

A tag management system that lets you deploy and update tracking tags (GA4, Google Ads, Meta) through a web interface, without editing site code each time.

GTM's building blocks: a tag does something (sends data), a trigger decides when it fires, and a variable supplies dynamic values.

A JavaScript object on your site that holds structured data (page type, product details, user state) for GTM to read and pass to tags.

Running a GTM container on a server you control, so tracking requests go through your own endpoint instead of directly from the browser.

Google's framework for adjusting tag behaviour based on user consent. Consent Mode v2 lets GA4 model conversions lost to consent denials.

Data you collect directly from your own audience, increasingly important as third-party cookies decline. Server-side tagging helps you collect it reliably.

Tags appended to campaign URLs (utm_source, utm_medium, utm_campaign) that tell GA4 where traffic came from.

An API for sending events to GA4 directly from a server, used for offline conversions and server-side enrichment.

A Google Ads feature that uses hashed first-party data to recover conversions that cookies miss, improving measurement accuracy.

Tying inbound phone calls back to the source, campaign and keyword that drove them, so phone leads can be reported and counted as conversions alongside forms.

A call tracking technique that swaps the phone number on your site for a tracking number tied to each visitor or traffic source, so a call can be matched to the visit that produced it.

Meta's server-side API for sending conversion events directly to Meta, deduplicated against the browser Pixel for more complete ad data.

Google's free reporting tool (formerly Looker Studio) for building interactive, shareable dashboards from GA4 and other sources.

A field in Google Data Studio defined by a formula, used to create custom metrics or reshape dimensions (such as custom channel groupings).

Combining multiple data sources (for example GA4 and Google Ads) into one Google Data Studio chart by joining them on a shared key.