When we use above as a preposition, it means ‘higher than’. Its meaning is close to that of the preposition over. In the following sentences, over can be used instead of above:
The waves came up above her head and she started screaming. (or … came up over her head …)
She is a nervous flier. But once the plane got above the clouds, she started to relax. (or … got over the clouds …)
We use above, but not over, to refer to things that are at an upper or higher level:
[a ‘chalet’ is a small wooden building usually found in mountainous areas]
Do they live in that chalet above the village?
Not: Do they live in that chalet over the village?
We usually use above, but not over, when there is no contact between the things referred to. Over or on top of have a more general meaning, and can be used when one thing touches or covers another:
They made her comfortable and put a blanket over her.
Not: They made her comfortable and put a blanket above her.
We normally use over not above with numbers:
I get over sixty emails a day.
Not: I get above sixty emails a day.
If you weigh over 100 kilograms, then you may need to start a diet.
Not: If you weigh above 100 kilograms
When we talk about temperatures in relation to zero or (the) average, we use above not over:
It was three degrees above zero.
Not: It was three degrees over zero.
When we refer to temperatures in other contexts, we can normally use above or over:
The temperature is already above 30 degrees. (or … over 30 degrees.)
We don’t use over to mean ‘higher level’.
Most of the race is 500 metres above sea level.
Not: Most of the race is 500 over sea level.
We don’t use above when one thing touches or covers another.
Pour some cream over the tart and serve it warm.
Not: Pour some cream above the tart
We don’t use above with numbers.
Over 100 people complained about the programme.
Not: Above 100 people complained