The title tag is an HTML element that names a page. Search engines usually show it as the clickable headline in results, although Google sometimes rewrites it.
Why it matters
It's one of the clearest signals of what a page is about, and it's the first thing searchers read. A clear, specific title earns more clicks than a vague one at the same position.
Example
"Blog post 14 | Fernbrook" tells nobody anything. "Cold brew ratio: the simple guide for 1 cup to 1 gallon" matches the search and promises an answer.
What to do
Put the main topic near the start, keep it short enough to show in full (roughly 50 to 60 characters), make it specific, and give every page a different title.