Translating this word very literally is very awkward in English –"the One who causes to return" – but economical in Hebrew. At the root of the word are the three letters chet-zayin-resh, bearing the notion of "return."
Another word in the vocabulary of prayer also carries the notion of returning. We often talk about the idea of repentance, t'shuvah, as being one of turning aside from objectionable behavior and returning to a life of righteousness. Hidden within this welcoming notion is the inference that the "turning aside" may not be so natural, and that the "returning" we are doing may not be to such a familiar place. Often t'shuvah is less return than restoration or rehabilitation.
But with ch-z-r comes the idea that the return is to a place that is already a part of personal history. This kind of returning is a homecoming of sorts. That is why a form of this word is commonly used when a promise is made to return from a trip, short or long, or to repeat an attempt that has been unsuccessful. It is why a form of this word is combined with the notion of t'shuvah for the one who elects to "come back to God" by embracing a religious life style: she is called a "chozeret bit'shuvah"/he is called a "chozer bit'shuvah," which sounds redundant if translated as someone who "returns to returning," but clarifies the distinction if we say "returns in repentance."
This distinction is very important in the context of this particular prayer. We describe God as the One who causes [something] to return. Whatever it is that God is causing to return thus had to have been lost from its proper place. Whatever God is causing to return belongs in that place. It belongs in its home. There is no renewal, restoration or rehabilitation necessary – though the result of return may or may not be any of those things. But the lost object is whole and rightfully returned to its proper place.
Sometimes our prayers are meant to inspire, and other times to educate. And more than occasionally, both.