on top of

{prep}. 1. On the top of; standing or lying on; on. * /When the player on the other team dropped the ball, Bill fell on top of it./ * /That high hill has a tower on top of it./ 2. {informal} Very close to. * /The elevator was so crowded that everybody was on top of each other./ * /I couldn't find my umbrella and then I realized I was almost on top of it./ 3. {informal} In addition to; along with. * /Mrs. Lane had many expenses and on top of everything else, her baby became ill./ * /Mary worked at the store all day and on top of that she had to baby-sit with her brother./ 4. {informal} Managing very well; in control of. * /Although his new job was very complicated, John was on top of it within a few weeks./ * /No matter what goes wrong, Mary always stays on top of it./ 5. Knowing all about; not falling behind in information about; up-to-date on. * /Mary stays on top of the news by reading newspapers and magazines./ * /When he was in California, Mr. Jones kept on top of things in his office by telephoning every day./