Ok, this is a complicated one so I referred to Miriam Webster Dictionary for a detailed response to your question. Here are the most useful comments: Both above and over function as adverbs, prepositions, and adjectives, but since there is no overlap in meaning with the adjectives, only the adverbs and prepositions are mentioned here. In its most common senses, the adverb over implies movement from one location or position to another: They climbed over the fence. He leaned over to see what I had written. I knocked over a glass of water. The baby is learning to roll over. She moved over to make room for them. Would you come over here for minute? I know you have the key. Hand it over, please. == The senses of the adverb above that function similarly imply only location, not movement: We lay on our backs and looked at the clouds above. Some children are fascinated by the moon and the stars above. The maze looks like person's face when viewed from above. You can write to us at the address shown above. == As prepositions, both over and above can mean "at or to a place that is higher than someone or something," but over is somewhat more common: A light hangs over/above the table. He raised his arms over/above his head. She rents an apartment over/above a bookstore. == Both can also mean "more than something": The movie is suitable for children over/above 13 years old. We've been having temperatures over/above 90 degrees Fahrenheit. I value time over/above money. I hope that helps!

I like the in-depth explanation that Julie supplied. Though, here is a simplified version...maybe? It just depends on how you USE the word.. These are all correct examples: 1. The ball flew over the fence. 2. The helicopter was hovering over the building. 3. The helicopter was hovering above the building. 4. We practiced the same lesson over and over again. 5. We went over the last lesson. (This means the same as reviewing) 6. She went over to that persons house. 7. Look at the stars above us. 8. That shooting star just went over the moon. The word 'over' will be used when something is physically moving to another location. (but it is okay to say something like 'the helicopter is floating over...') The word 'above' will be used when something is stating the actual location of something that is located 'above' something.