1 everything that happened in the past, more specially since humans learned to write.
2 everything that got written down and was accepted as "the history" by some elite or another.
3 the field of study of 1 and 2. Discusses all kinds of explanations of what happened.
4 a school subject devoted almost exclusively to 2.
1 Johnny Cash is history.
2 The history of the colonization of America has little to do with what actually happened.
3 An interesting question in history is whether guns, diseases or beliefs were more important factors in eliminating the Native Americans.
4 History is quite boring, especially if it's about your own country.