Every analytics tool uses the same handful of words for slightly different quantities, which is why two dashboards disagree before either has counted anything wrong. Here are ours, stated exactly, so you can line them up against whatever you are comparing them to.
Pageview
One page being shown. A reload counts. A navigation inside a single-page application counts, because the visitor has gone somewhere even though the browser did not reload — and a tool that misses those reports one pageview for an entire session on an app-shaped site, which makes every page-level report meaningless.
Visit
A run of activity from one person that ends after thirty minutes of inactivity. A gap of exactly thirty minutes still extends it; thirty minutes and one second starts a new one.
A visit is also capped at one day. That ceiling exists for the tab somebody opens on Friday and closes on Monday: without it, one person distorts the average duration for everybody, and the distortion grows with the length of the window.
Visitor
One person, counted once per UTC day. The mechanism that lets us count them without storing anything about them also stops us recognising them tomorrow, which is the single most important definition on this page to get straight before comparing anything.
It means a daily visitor count is exact, and a monthly figure built by adding days up is not a count of people — it is the sum of daily counts, in which somebody who visits on five days appears five times. Useful, consistent, and a different quantity from the monthly users of a tool that keeps an identifier.
Current visitors
Anyone active in the last five minutes. Shorter than the visit window on purpose: "right now" should mean right now, and stretching it to thirty minutes makes a quiet site look busy.
Event
Something you asked us to count — a signup, an outbound click, a purchase. Events and pageviews are both metered against your allowance, which is the norm in this category and is worth checking against what you were paying before, because a tool that meters only pageviews and one that meters both are not comparable on price alone.
Bounce, and why it is a definition rather than a verdict
A bounce is a visit with one pageview. That is all it is — and the reason it deserves its own line here is that the word carries an implication the measurement does not support. A visitor who arrived, read the whole answer they came for, and left satisfied is a bounce. So is one who landed on the wrong page and left immediately. The number cannot tell them apart, and a page that exists to answer one question will always have a high one.
What is deliberately not defined
There is no "returning visitor" metric, because there is no way to produce one honestly without keeping something that identifies a person across days. Rather than offer an approximation that would be wrong in a way nobody could see, the metric is absent. The same reasoning rules out anything described as a user journey across sessions.
Absent is the right answer when the alternative is a number that looks precise and is not. A missing metric prompts a question; a wrong one does not.
Why the definitions are the first thing to check
When two tools disagree, the instinct is to look for a fault. Usually there is no fault: one is reporting sessions that end after a different interval, or users recognised across a different span, and the numbers are each internally consistent. Why analytics tools never agree covers the mechanical causes once the definitions are lined up, and the alternatives page is the place to start if you are still choosing.