An editorial cartoon is an illustration expressing opinion about a topic. It uses visual elements like characters, symbols, and dialog boxes to tell a story and convey a viewpoint in a single-panel cartoon. The goal is to entertain readers while informing them and shaping opinions on issues through humor and persuasive messaging. Key aspects of editorial cartoons include composition techniques like the rule of thirds, use of symbols over literal representations, and technical elements like lettering and lines to depict movement.