What is the Difference in meaning between these two words ?
"avenge" is a verb /to punish or hurt somebody in return for something bad or wrong "revenge" is a noun / something that you do in order to make somebody suffer because they have made you suffer
In more formal or literary English, revenge can also be a verb. People revenge themselves on somebody or are revenged on them (with the same meaning):He was later revenged on his wife’s killers. You cannot revenge something