• Link - WordNet

Not sure if WordNet qualifies as the "Semantic Web", but it's definitely semantic whatever the format may be. From the site ( paraprased )

WordNet® is a lexical database containing nouns, verbs, adjectives and adverbs. They aregrouped into "synsets" ( sets of cognitive synonyms ) each expressing a distinct concept. Conceptual-semantic and lexical relations build links between synsets. A browser navigates through the network of meaningfully related words and concepts.