The web analytics glossary. Plain definitions of the terms that end up in a report, with the formula, a worked example, and an honest note on what each number cannot tell you.
In short
What do web analytics terms actually mean?
Web analytics terms describe three different things: units of traffic such as pageviews, sessions and visitors, rates calculated from them such as bounce rate and conversion rate, and methods applied to them such as funnels and cohort analysis. Most confusion comes from tools defining the same word differently.
That last point is the reason this glossary exists. Bounce rate, session and unique visitor all mean subtly different things depending on which tool produced the number, and a report that mixes two definitions is worse than one that has neither. Every entry here states the definition it is using, and where tools disagree, it says so.
Categories
Analytics foundations
- Digital analyticsDigital analytics is the measurement and analysis of customer behaviour across every digital channel a business operates: website, mobile app, email, advertising platforms, support and in-product usage.
- EventAn event is any recorded action beyond loading a page: a button click, a form submitted, a video played, a subscription upgraded.
- Product analyticsProduct analytics is the measurement of what people do inside a product rather than how they arrived at it.
- SessionA session is one continuous visit to a site: a group of pageviews and events from the same visitor with no long gap between them.
- Web analyticsWeb analytics is the collection, measurement and analysis of what happens on a website: who visits, where they came from, which pages they see, and what they do before they leave.
Metrics and measurement
- Bounce rateBounce rate is the share of sessions that end without a second interaction: one page loads, nothing else is recorded, and the visitor leaves.
- Churn rateChurn rate is the share of customers, users or revenue lost during a period.
- Conversion rateConversion rate is the share of visits or visitors that completed a defined goal, such as a signup, a purchase or a demo request.
- DAU/MAU ratioDAU/MAU is daily active users divided by monthly active users, expressed as a percentage.
- Engagement rateEngagement rate is the share of sessions that met a defined engagement threshold rather than leaving immediately.
- Exit rateExit rate is the share of views of a given page that were the last page of the session.
- Good bounce rateThere is no universal good bounce rate.
- North star metricA north star metric is the single number a company chooses to represent the core value its product delivers to customers.
- PageviewA pageview is a single recorded view of a page on your site.
- Retention rateRetention rate is the share of users from a starting group who are still active at the end of a defined period.
- Time on pageTime on page is how long a visitor spent on one page before moving to the next.
- Unique visitorA unique visitor is one person counted once within a reporting period, no matter how many times they visit or how many pages they view.
Traffic and attribution
- Attribution modelAn attribution model is the rule that decides which marketing touchpoints get credit for a conversion when a customer interacted with several before buying.
- Dark trafficDark traffic is genuine human traffic whose origin analytics cannot see, because the referrer header was stripped and no campaign tag was present.
- Direct trafficDirect traffic is every visit that arrives with no referrer and no campaign parameters, so analytics has nothing to attribute it to.
- Landing pageIn analytics, a landing page is the first page a visitor sees in a session, whatever page that happens to be.
- Referrer spamReferrer spam is fake traffic sent with a forged referrer header so that the spammer's domain appears in your referral report and tempts you to visit it.
- UTMA UTM is a set of query parameters added to the end of a link so that analytics can tell where a click came from.
- UTM parametersUTM parameters are the five named query-string values that describe a campaign link: utm_source, utm_medium, utm_campaign, utm_term and utm_content.
Privacy and tracking
- Cookie bannerA cookie banner is the notice that asks a visitor's permission before storing or reading information on their device.
- Cookieless analyticsCookieless analytics measures website traffic without storing a cookie, a localStorage value or any other identifier on the visitor's device.
- Cookieless trackingCookieless tracking is any method of recognising visits without storing an identifier in the browser.
- First-party dataFirst-party data is information you collect directly from your own audience on your own properties: site behaviour, purchases, support conversations, and anything customers tell you.
- Server-side trackingServer-side tracking sends analytics events from your own backend rather than from the visitor's browser.
- Tracking pixelA tracking pixel is a tiny, usually invisible image embedded in a web page or an email.
Analysis methods
- Cohort analysisCohort analysis groups users by something they share, usually the week or month they signed up, then tracks each group separately over time.
- Conversion funnelA conversion funnel is an ordered sequence of steps a visitor takes toward a goal, measured by how many people reach each step.
- Core Web VitalsCore Web Vitals are three metrics Google uses to measure page experience: Largest Contentful Paint for loading, Interaction to Next Paint for responsiveness, and Cumulative Layout Shift for visual stability.
- HeatmapA heatmap is a visualisation that overlays aggregate visitor behaviour onto a screenshot of a page, using colour to show intensity.
- Session replaySession replay reconstructs a visitor's session as a playable recording of what happened on screen.
FAQ
What is web analytics?
Web analytics is the collection, measurement and analysis of what happens on a website: who visits, where they came from, which pages they see, and what they do before they leave. Its purpose is to inform decisions about the site rather than simply to report traffic.
What is the difference between a pageview, a session and a visitor?
They are three counts of the same traffic at three levels of grouping. A pageview is one view of one page. A session groups a visitor's pageviews into a single visit, ending after 30 minutes of inactivity. A unique visitor is one person counted once in the reporting period, however many sessions they produced.
Which analytics metrics actually matter?
The ones tied to an outcome. Traffic volume on its own answers nothing, so instrument conversions first, then read acquisition and behaviour metrics as explanations for how conversions moved. Three metrics everyone agrees on beat forty nobody has read.
Do these metrics work without cookies?
Almost all of them. Everything scoped to a session works cookielessly: pageviews, sessions, sources, campaigns, funnels, engagement and revenue. What needs persistent identity is anything spanning days, such as retention, cohorts and DAU/MAU, which needs either an optional cookie mode with consent or your own user id.
Why do two analytics tools report different numbers for the same site?
Different session timeouts, different bot filtering, different handling of client-side navigation in single-page apps, and different exposure to adblocking. A gap of 10% to 20% between two tools on the same site is normal. Compare each tool against its own history rather than against the other.
Put the definitions to work
- Analytics without cookies, and without a banner by default
- Work the numbers out with the free calculators
- Turn a conversion rate into a funnel you can act on
- Watch the sessions behind a number with session replay
- Attribute revenue to the campaigns that produced it
- Read the mrkr documentation
- See what mrkr costs
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