13. A system comprising: one or more computers; and a computer-readable medium coupled to the one or more computers having instructions stored thereon which, when executed by the one or more computers, cause the one or more computers to perform operations comprising: traversing a corpus of documents to identify a plurality of lists within the documents, wherein each list comprises structured data delimited from other data in a document, and wherein each list specifies an enumeration of elements; selecting a pair of terms based on determining that both terms of the pair are contained in a first quantity of lists that are included in the documents in the corpus, wherein the first quantity is more than a first predetermined quantity, and wherein each list in the first quantity of lists includes more than a second predetermined quantity of terms; determining a first value that represents a quantity of documents in the corpus that include a list that contains both terms of the pair; determining a second value that represents a quantity of the documents in the set corpus that include a list that contains at least one of the terms of the pair; when both terms of the pair are contained in the first quantity of lists that are included in the documents in the corpus, determining a correlation value from the first value and the second value; determining that the correlation value satisfies a threshold; and designating the pair of terms as potentially non-synonymous terms by adding the pair of terms to a blacklist, based on determining that the correlation value satisfies the threshold, wherein the blacklist is accessed for synonym determination.
13. A system comprising: one or more computers; and a computer-readable medium coupled to the one or more computers having instructions stored thereon which, when executed by the one or more computers, cause the one or more computers to perform operations comprising: traversing a corpus of documents to identify a plurality of lists within the documents, wherein each list comprises structured data delimited from other data in a document, and wherein each list specifies an enumeration of elements; selecting a pair of terms based on determining that both terms of the pair are contained in a first quantity of lists that are included in the documents in the corpus, wherein the first quantity is more than a first predetermined quantity, and wherein each list in the first quantity of lists includes more than a second predetermined quantity of terms; determining a first value that represents a quantity of documents in the corpus that include a list that contains both terms of the pair; determining a second value that represents a quantity of the documents in the set corpus that include a list that contains at least one of the terms of the pair; when both terms of the pair are contained in the first quantity of lists that are included in the documents in the corpus, determining a correlation value from the first value and the second value; determining that the correlation value satisfies a threshold; and designating the pair of terms as potentially non-synonymous terms by adding the pair of terms to a blacklist, based on determining that the correlation value satisfies the threshold, wherein the blacklist is accessed for synonym determination. 18. The system of claim 13 , wherein determining a correlation value from the first value and the second value comprises calculating the correlation value by dividing the first value by the second value.