¡¡¡¡UV stands for Unique Visitor. This can be a metric that you can judge your websites popularity. Every time a visitor comes to your website it would be counted as an unique visitor. If someone used your computer after you and also visited the website, there is possibility that this would not be counted by your statistics program. As with all statistics there is the possibility that they are not 100% accurate.
¡¡¡¡A unique visitor is a statistic describing a unit of traffic to a website, counting each visitor only once in the time frame of the report. This statistic is relevant to site publishers and advertisers as a measure of a site's true audience size, equivalent to the term "Reach" used in other media.