Cross-country races are a popular form of long-distance running, typically taking place off-road in natural environments. Synonyms for the term "cross-country races" include trail running, endurance running, ultrarunning, hill running, and fell running. Trail running refers to running on trails through natural terrain, while endurance running typically refers to races longer than a marathon distance. Ultrarunning involves running distances beyond a traditional marathon, usually over 50 kilometers. Hill running and fell running emphasize running on steep gradients and hills, respectively. These synonyms offer different perspectives on the sport of cross-country racing, showcasing the varied challenges and terrain involved in these races.