Officially nothing, but they suggest if anything it could stand for Compact High Rider. See this article here: http://www.forbes.com/sites/bertelschmitt/2016/12/13/playful-fun-for-adults-toyota-finally-releases-its-c-hr-compact-crossover-at-home/#36f205107510
Wiki says it could be one of three names: The name C-HR stands for Compact High Rider, Cross Hatch Run-about or Coupé High-Rider.
Wiki says it could be one of three names: The name C-HR stands for Compact High Rider, Cross Hatch Run-about or Coupé High-Rider.