加油 as a Term of Encouragement

The Chinese characters say 加油 (Jia1 you2).加 is composed of 力 (power) and 口 (mouth). It means 'to add'油 is made out of 水 (氵, water) and 由(from/ due). It means oil.加（to add） 油（oil）= add oil or make an extra effort 加油 is a terribly common phrase in day to day life. If you want to encourage someone to carry on great work, or in a sports competition, you say 加油! A bit like 'go on!' in English. Of course another literal meaning of 加油 is to refuel.