In various embodiments, methods and systems for implementing a semantic signature system are provided. A semantic signature system provides a machine trained semantic representation (i.e., a semantic signature) of the context of a word, synonyms of the word, and weak and strong relationship of the word with other words. The semantic signature can be utilized to facilitate labeling a word that is ambiguous or previously unknown. In practice, the label can be used to more accurately categorize the word for later retrieval by a search or to more accurately provide search results for a search query that includes the word.