The word was first originated from ancient China; although nowadays it's more often used in Buddhism, in fact it first appeared in the Taoism classic - Zhuang Zi. It's original meaning is "very hard and frequent walking/practice". Philosopher Zhuangzi abstracted and modified this word from an earlier classic of Taoism - Laozi's Tao Te Ching, in which it states:“上士闻道，勤而行之。”, which means taking effort and practicing.