1. A method establishing is-a relationships, the method comprising: receiving, by a server, a query from a user, the query including a string and one or more context words; retrieving homonym concepts corresponding to the string and concept vectors for each homonym concepts; comparing the concept vectors to the one or more context words; selecting at least one homonym concept according to the comparison; retrieving from a category-concept mapping database at least one category for the selected at least one homonym concept, the category-concept mapping database establishing is-a relationships between the a plurality of categories and plurality of concepts; and transmitting, by the server, the retrieved at least one category for display to the user.