A vlog is a blog made of video instead of writing. One person points a camera at themselves and talks — about their day, their opinions, their trip, what they bought — and posts it, usually on YouTube, usually as part of an ongoing series. The heart of it is that a real named person is speaking to you directly, in their own voice; a company advertisement with video in it is not a vlog, and a film with actors is not a vlog. The word is both a noun and a verb: you can watch someone's vlog, and you can vlog your holiday. Verb forms are vlogs, vlogged, vlogging. It is casual, everyday internet English — you would not put it in a formal report without explaining it — and it belongs mostly to the last twenty years. Note that the older dictionary wording calls it a website; that was true when the word was new, when people had their own vlog sites. Now a vlog is almost always a channel or a series of videos inside a big platform, not a site of its own, and a single video can also be called "a vlog". Sound: it starts with a v then straight to an l, "vlog", one syllable.