3. The method of claim 1 , wherein extracting the one or more n-grams from communications associated with the visual-media items comprises filtering out one or more non-descriptive n-grams from a plurality of n-grams included in the communications, wherein the non-descriptive n-grams are present on a pre-generated list of non-descriptive n-grams.
1. A method comprising, by one or more computing systems: identifying a shared visual concept in two or more visual-media items, wherein each visual-media item comprises one or more images, each image comprising one or more visual features, and wherein each visual-media item comprises one or more visual concepts, the shared visual concept being identified based on one or more shared visual features in the respective images of the visual-media items; extracting, for each of the visual-media items, one or more n-grams from one or more communications associated with the visual-media item; generating, in a d-dimensional space, an embedding for each of the visual-media items, wherein a location of the embedding for the visual-media item is based on the one or more visual concepts included in the visual-media item; generating, in the d-dimensional space, an embedding for each of the extracted n-grams, wherein a location of the embedding for the n-gram is based on a frequency of occurrence of the n-gram in the communications associated with the visual-media items; associating with the shared visual concept, one or more of the extracted n-grams that have embeddings within a threshold area of the embeddings for the identified visual-media items; populating a visual-concept index that indexes visual concepts with their respective associated n-grams; receiving, from a client system of a user, a search query comprising one or more n-grams; determining, based on the visual-concept index, one or more visual concepts associated with the n-grams of the search query; and sending, to the client system of the user, one or more search results comprising visual-media items in which the determined visual concepts are identified.