ger ‧ ry ‧ man ‧ der ‧ ing /ˈdʒerimænd ə rɪŋ/ BrE AmE noun [uncountable]
[ Date: 1800-1900 ; Origin: Elbridge Gerry (1744-1818), US politician + salamander ; because a voting area he made to help his own party win an election was said to be shaped like a salamander ]
when politicians change the size and borders of an area before an election, so that one person, group, or party has an unfair advantage
—gerrymander verb [intransitive and transitive]