Gerrymandering

In the process of setting electoral districts,gerrymandering is a practice that attempts to establish a political advantage for a particular party or group by manipulating district boundaries to create partisan advantaged districts. The resulting district is known as a gerrymander (/ˈɡɛrimændər/, alt. /ˈdʒɛriˌmændər/); however, that word can also refer to the process. When used to allege that a given party is gaining disproportionate power, the term gerrymandering has negative connotations.

In addition to its use achieving desired electoral results for a particular party, gerrymandering may be used to help or hinder a particular demographic, such as a political, ethnic, racial, linguistic, religious, or class group, such as in U.S. federal voting district boundaries that produce a majority of constituents representative of African-American or other racial minorities, known as "majority-minority districts".

Source: Wikipedia