A visitor is also called a unique visitor.
Using a cookie or a hash value (in the case of cookie-less tracking), etracker can recognize website visitors on a subsequent visit.
If a website visitor visits a website again, they are only recorded in the statistics as a new visit but not as a new visitor.
A website visitor with a cookie is therefore only counted as a visitor once within a given period, regardless of how often they return.
Hence the term “unique visitor”.