1. One or more computer-storage media storing computer-useable instructions that, when used by one or more computing devices, cause the one or more computing devices to perform a method of utilizing a per-document index in combination with an inverted index to identify contextually-relevant search results, the method comprising: at a search service: receiving a search query comprising one or more keyword terms and one or more surrounding terms; determining a contextual meaning for the search query based on the one or more keyword terms and the one or more surrounding terms in the search query; accessing an inverted index stored in association with a first data store associated with the search service; using the one or more keyword terms of the search query, identifying a set of documents in the inverted index containing the one or more keyword terms; subsequent to accessing the inverted index, accessing, forward encoded per-document indexes associated with each document in the set of documents, the forward encoded per-document indexes stored in association with a second data store associated with the search service; using the forward encoded per-document index for the each document in the set of documents, analyzing the one or more keyword terms and surrounding terms in the each document to determine a respective contextual meaning for the each document; ranking the each document in the set of documents based on the each document's respective contextual meaning as compared to the contextual meaning of the search query, the documents in the set of documents having a respective contextual meaning most relevant to the contextual meaning of the search query ranked higher than the documents in the set of documents having a respective contextual meaning less relevant to the contextual meaning of the search query; and communicating for presentation on a search results page the ranked set of documents in a rank-ordered list.