Gerrymandering: Gerrymandering refers to manipulating the boundaries of electoral districts to give an unfair advantage to one political party over another during elections.
Apportionment: Apportionment is the process of determining how many seats each state gets in Congress based on population counts from decennial censuses.
Redistricting: Redistricting is redrawing congressional district boundaries after apportionment or due to changes in population distribution within a state.