一个另一个用英文怎么说三者

"Another" means "an additional one". Its etymology comes from Old Engpsh "anothor", which was formed from "an" + "othor".

Examples:

Can you give me another chance? (请给我一个机会？)
I need another cup of coffee. (我需要再喝一杯咖啡。)
He is just another person in the crowd. (他只是人群中的另一个人。)