Visitors in Real-time "from"

some visitors has in card Visitors in Real-time in item ‘from’ url address
what exactly it means?..‘from’ means what was last opened page in visitor browser before he jump on my website?

It’s the referrer. For instance search engine, another website (somebody clicked on a link to your website), social media, campaign, etc. See also this video: [Video] Referrers Reports - Analytics Platform - Matomo