Gerrymandering is a practice intended to establish a political advantage for a particular party or group by manipulating district boundaries. The resulting district is known as a gerrymander (i-/); however, that word is also a verb for the process. The term gerrymandering has negative connotations. Two principal tactics are used in gerrymandering: "cracking" (i.e. diluting the voting power of the opposing party's supporters across many districts) and "packing" (concentrating the opposing party's voting power in one district to reduce their voting power in other districts). The third tactic, shown in the top-left diagram in the diagrams to the right, is that of homogenization of all districts.
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". Gerrymandering can also be used to protect incumbents.
Gerrymandering should not be confused with malapportionment, whereby the number of eligible voters per elected representative can vary widely without relation to how the boundaries are drawn. Nevertheless, the -mander suffix has been applied to particular malapportionments. Sometimes political representatives use both gerrymandering and malapportionment to try to maintain power.