Semantic simply means “meaning”. The Semantic Web is not a separate Web but an extension of the current one, in which well-defined meaning is given to information, allowing computers and people to work better in cooperation. In today’s web, most web pages add basic semantics for search engines using the tag; however, they are simply keywords in isolation and lack links to provide more meaningful context. This semantics is weak and limits searches to exact matches.
Semantics gives useful meaning to a keyword symbol by establishing relationships. (For example, a stand-alone keyword such as building exists on a web page. The tag surrounds the keyword building to indicate its importance. However, if the keyword is related to other keywords in defined relationships, a data network or forms of context, that reveals Therefore, construction is related to several other keywords, such as architect, building plans, construction site, etc., the relationships expose the semantics.
Therefore, the Semantic Web is simply a network of data described and linked to establish a context or semantics that adhere to defined grammatical and linguistic constructs.
The WWW is primarily made up of content for human consumption. Content links to other content on the WWW through the Universal Resource Locator (URL). The URL relies on the surrounding context (if any) to communicate the purpose of the link it represents; normally the user infers the semantics. Web content usually contains formatting instructions for good presentation, again for human consumption. WWW content has no formal logical constructs. Consequently, the Semantic Web consists primarily of statements for consumption by applications. The statements are linked to each other through constructions that can form the semantics, the meaning of the link. Therefore, link semantics provide a defined meaningful path rather than a user-interpreted one. The statements may also contain logic that allows further interpretation and inference of the statements.
The Semantic Web is solidly based on graph theory and description logic. Statements and corresponding relationships establish both concepts (eg, a Person has a date of birth) and instances (eg, John is friends with Bill). Statements that define concepts and their relationships form ontology. Statements referring to individuals form instance data. Statements can be asserted or inferred. The first requires the application to create the statement directly, to assert the statement. The latter requires a reasoner to infer additional statements logically. (That John is an associate of Bill is inferred from the asserted statements.) The Semantic Web offers several languages. Instead of having one language that fits all information and programming needs, the Semantic Web offers a range from basic to complex. This provides Semantic Web applications with options to balance their needs for performance, integration, and expressiveness. There is a set of declarations that contribute to the Semantic Web mainly in two ways; knowledge bases and archives. The knowledge base offers dynamic and extensible storage similar to relational databases. Files usually contain static declarations.