Semantics are the implied meaning of a subject, like a word or sentence. It aids how humans (and these days, machines) interpret subject matter. On the web, HTML serves both humans and machines, suggesting the purpose of the content enclosed within an HTML tag. Since the dawn of HTML, elements have been revised and adapted based on actual usage on the web, ideally so that authors can navigate markup with ease and create carefully structured documents, and so that machines can infer the context of the wonderful collection of data we humans can read.
HTML5: Let’s Talk about Semantics