Preposition
Atop
Very close to, in any orientation or in time.
Living on top of one another in a refugee camp is stressful.
At peak times, a telephone operator must handle a number of calls, one on top of the next.
(idiomatic) In addition to something else.
[…] and on top of all that, I got a puncture!
(idiomatic) Fully informed about, and in control of, something; up to speed with.
I have sorted out the problems and am now on top of the situation.
You will need to get on top of your nutrition in addition to training for washboard abs.
to feel on top of the world
Most software today is very much like an Egyptian pyramid with millions of bricks piled on top of each other, with no structural integrity, but just done by brute force and thousands of slaves. Alan Kay
Anytime you see a turtle up on top of a fence post, you know he had some help. Alex Haley
Let a man find himself, in distinction from others, on top of two wheels with a chain - at least in a poor country like Russia - and his vanity begins to swell out like his tires. In America it takes an automobile to produce this effect. Leon Trotsky
As if it weren't bad enough to fall, the ladder lands on top of you. Malawi Proverb
A lizard that fell from the top of a tree wastes its time looking back to where it fell from; if there was anything good the lizard deserved, it could not have missed it while it was there on top of the tree. Nigerian Proverb
When you see a turtle on top of a fence post, you know he had some help. African Proverb