Specify a relevance weight for hits that occur in listed fields (example: Subject:10,HtmlTitle:20)

FieldWeights is a list of field names, with a weight indicated after each field name, like this:

Hits that occur in one of these fields will count more heavily than other hits, according to the weight you specify. For more information, see "Relevance" in the "Overviews" section of the API documentation.