Here is a word that changed meanings entirely from the Bible to the time of the rabbis, and still manages to mean the same thing. In doing so, it provokes intriguing ideas about the context of creation and essence of life.
The prefix "l" means "to," but should not be taken too literally in the context of the idiom that "l'olam" begins. It is helpful, at the moment, to ignore it.
"Olam" is usually translated as "world," and that translation is mostly accurate but, as with all translation, not entirely adequate. In the Bible, "olam" means the world of time. You have encountered this meaning in the frequent idiom "mei-ata v'ad olam," which means "from now until forever," or "from now until the end of time."
But through a process no one can identify, by the time of the Mishnah, and therefore before the composition of the prayer book, "olam" had come to mean the world of space, that is, nature or the whole of physical existence. References to "this world and the world to come" or (much later) "the whole world is a narrow bridge" are spatial references.
Even in those few words of explanation, it is clear that the two meanings impact each other. The end of time, to human beings, is the end of the world on both an individual and collective basis. A "world to come" mixes the spatial (world) with the temporal (to come). And though neither the Bible nor the prayer book could anticipate the language of science, our very concept of time is a function of the cycles of our physical world – a system we human beings invented to keep track of our own lives.
In these few words it is impossible to raise the delicious questions implied by this space-time connection – never mind attempting to answer them. But the use of this word in its common idiom in prayer always brings us to a boundary at the edge of life. By saying its very name, it requires us to think "and what comes beyond that?"
If part of the function of prayer is to remind us of the ultimate concerns we mortals should consider, then this multi-faceted "olam" may be the essential word. And when "olam" reminds us of the realm created and delineated by God, it also reminds us that God is not contained by the "olam" of God's creation – just the opposite.