on top of

preposition4

1. •
   Atop.

   • There's a house on top of the mountain.
2. •
   In addition to something else.

   • […] and on top of all that, I got a puncture!
3. •
   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.
4. •
   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.