Ummah translates to community in Arabic. Furthermore this is exactly what is meant by the term.
You can find the ummah across the whole globe and muslims are encouraged to keep a community in Islam for several reasons:
Knowledge
Knowledge is meant to be shared
Helps spread the religion
Advice on matters
Safety
Expectation of an Islamic culture
You will be looked after by any member of the ummah
Feel more comfortable in an area that contains the Ummah
Care
Part of a Muslims religion to look after people regardless of status
Quote for if one of us is hurt then all of us are
In Islam it’s not just a word, it’s a concept.