A is above/over B.
The snow came up above/over our knees.
There s a spider on the ceiling just above/over your head.
A is above B. (not A is over B )
A /’s over B.
There is cloud over the South of England.
And we use over when one thing crosses another. (Across is also possible.)
A is (moving) over/across B.
Electricity cables stretch over/across the fields.
The plane was flying over/across the Channel.
- ‘How old are you?’ Over thirty.’
He’s over two metres tall.
There were over fifty people at the party.
But we use above in some expressions, particularly when we are thinking of a vertical scale.
Examples are: above zero (for temperatures); above sea-level; above average.
For the difference between over and across, see 4.
For other meanings of above and over, see a good dictionary.