Manipulating legislative district lines to favor a political party or group is referred to as

The answer is gerrymandering. It is a practice intentional to institute a political advantage for a specific party or group by manipulating district boundaries. The resulting district is known as a gerrymander; on the other hand, that word can also refer to the procedure. The term gerrymandering has negative implications. Two chief strategies are used in gerrymandering: "packing" meaning concentrating the opposite party's voting power in one district to reduce their voting power in other districts and "cracking" meaning reducing the voting power of the opposing party's supporters across many districts.