Is there the concept of awrah between Muslim women?

Yes, according to the majority of scholars, the awrah for one female in front of another female will be what is between the navel and the knee. For example, we often get the question about a sister who's breastfeeding, is she allowed to do that in a particular area? Yes, what is above the navel is not considered to be part of the awrah for a female, it's between the navel to the knee. In the Hanafi Madhab, this does differ slightly, whereby this is the awrah for a Muslim female to another Muslim female. If you're in front of non-Muslim females in the Hanafi Madhab, you'd still need to cover as you would normally do in front of non-mahram males. That's specific to the Hanafi Madhab and they have the evidence and so on. But the majority view, as I mentioned, for a Muslim female in front of any other Muslim female, it is between the navel and the knee.