It is popularly interpreted as establish the prayer.
But what is the meaning of establish the prayer, Why god is asking us to establish the prayer, Why not he is saying recite/read/perform the prayer 5 times.
In arabic "aqueem" has the meaning of not just establishing the prayer but also:
establish the prayer in a complete way.
This means: Doing the prayer at the right time and in the right way.
One could add: conserve it, keep it unchanged and continue with it and make it everlasting!
It's saying to "establish/keep up the system of Islam" one needs to look it up in context of al-Furqan. Surah 2 aya 3