The terms "langoustine" and "langostino" refer to different species. "Langoustine" typically refers to a European lobster, resembling a small lobster. In contrast, "langostino" usually refers to the squat lobster or "northern lobster," a different crustacean in North American and South American waters. They differ in size, habitat, and appearance, with langoustines resembling small lobsters, while langostinos are smaller and have a distinct appearance.