You have heard the word, but are not quite sure what it means. It is relatively simple. Politicians play games with voting district boundaries to insure incumbents win their districts easily, and the status quo can be maintained in Congress. Look as this hypothetical example taken from the Quora website and posted by Jameson Quinn, a Phd candidate at Harvard. (He ought to know.)
Below is a cartoon of the first ever gerrymandered district. The painter Gilbert Stuart was inspired by the
bizarre shape of an electoral district on a map he saw in a newspaper
editor’s office. He lampooned the snake-shaped district making it out to be some kind of antediluvian
monster. “That will do for a salamander,” he said to the editor. “Gerrymander!”, replied the editor to Stuart.
For the man responsible for the odd shape of that electoral district, in eastern Massachusetts, was Elbridge Gerry, governor of the state. Gerrymandering and money neatly explains this stark fact: Congress has an average 14% approval rating, but 95% of incumbents are re-elected!