A more thorough explanation:

Definition: Delineational gerrymandering is the practice of dividing a geographical area into electoral districts, often of highly irregular shape, to give one political party an unfair advantage by diluting the opposition's voting strength.

For example, when Massachusetts Governor Elbridge Gerry ran for reelection in 1812, members of his political party, the Anti-Federalists, altered the state's voting districts to benefit the party. One newly created district resembled a salamander, inspiring a critic to coin the word gerrymander by combining the governor's name, Gerry, with the ending of salamander. This is an example of delineational gerrymandering.

There are three kinds of delineational gerrymandering: cracking (or fracturing), packing, and stacking. Cracking involves dividing a strong opposition group into multiple districts to dilute their voting power. Packing involves concentrating opposition voters into a single district to limit their overall influence. Stacking involves combining two or more districts with a majority of opposition voters into a single district to limit their representation in other districts. These practices are used to manipulate electoral outcomes and give one party an unfair advantage.