1. A method in a search term suggestion engine of a computing device, the method comprising: receiving characters of user data as the characters are input, wherein the user data is at least part of a search term to be provided to a first application to search for the search term, wherein the first application is one of multiple applications on the computing device; receiving, from the first application, an indication of multiple suggestion sources; obtaining, from each of two or more of the multiple suggestion sources, one or more suggested search terms based on the received characters; combining the one or more suggested search terms into a combined set of suggested search terms; and returning the combined set of suggested search terms to a search user interface for presentation to a user, the returning including returning first suggested search terms received from a first one or more of the multiple suggestion sources within a threshold amount of time, waiting until second suggested search terms are received from a second one or more of the multiple suggestion sources, and returning, after returning the first suggested search terms, the second suggested search terms to the search user interface.
13. A method as recited in claim 1 , further comprising returning third suggested search terms received from a third one or more of the multiple suggestion sources within the threshold amount of time with the second suggested search terms if the third suggested search terms are to be included later in the combined list than the second suggested search terms.