1. A method performed by data processing apparatus, the method comprising: receiving, with one or more processors at a server, an input string having a plurality of terms, the input string being in a first form, wherein a given sequence of the plurality of terms refers to a geographic feature, wherein the given sequence is annotated with a geographic-feature type selected from a plurality of geographic-feature types each indicating a characteristic of an entity in the physical world corresponding to the geographic feature, and wherein the given sequence is stored in an annotated format with the geographic-feature type in a database of geographic labels prior to receiving the input string; transforming, with one or more processors, the input string from the first form to a second form, the transforming including: applying one or more rules to the input string to identify one or more terms for translation, the one or more identified terms being fewer than the plurality of terms, wherein at least some of the rules are applied in response to a match between a feature type of the respective rule and the geographic-feature type with which the given sequence is annotated to indicate the characteristic of the corresponding entity in the physical world, translating the identified one or more terms to one or more translated terms in the second form, and transliterating at least some of the remaining terms of the plurality of terms into transliterated terms in the second form, including selecting one or more transliteration rules for application in accordance with the indicated characteristic of the entity, wherein when the given sequence of the plurality of terms is annotated with a first geographic-feature type of the plurality of geographic-feature types, a first rule of the one or more rules identifies a specific term in the input string for translation in response to a match between a first feature type of the first rule and the first geographic-feature type, and when the given sequence of the plurality of terms is annotated with a second geographic-feature type of the plurality of geographic-feature types, a second rule of the one or more rules identifies the same specific term in the input string for transliteration in response to a match between a second feature type of the second rule and the second geographic-feature type, wherein the specific term is translated or transliterated to a term having the same grammatical form as the specific term; the method further comprising: concatenating, with one or more processors, at least the translated and transliterated terms to form a hybrid output string in the second form; and storing the hybrid output string in the database of geographic labels; and when a map of a geographic region including the entity is requested for display: (i) retrieving the hybrid output string from the database and (ii) providing, via a network interface, the hybrid output string along with map data for presenting the map with the hybrid output string at a client device.