What does Ummah mean in Islam as we know there are many different groups with different ideas about Islamic rules which call themselves Muslim so how can you call it Ummah?
The correct spelling is Ummah or Umma. The word literally means community or people. When it comes to Islam, it means the whole community of Muslims bound together by ties of religion- OED. You are right that there are many sects within the Muslim community, but the whole of it is considered Ummah. The word encompasses everyone who is a Muslim.
Ummah means nation or group.
But to my knowledge it is wider than one nation expecially when we talk about the prophet pbuh and islam. The prophet pbuh was given five things that no other prophet was given and one of those five things being that he was given to all mankind not just the islamic nation wheras the other prophets before him where given to one religion/nation so you are wrong to say the word ummah only specifically applys to muslims/islam.
Ummah is everyone being together as the prophet pbuh stated every prophet before him was given his nation to guide but Allah has given him everyone to guide. Also everyone knows Jesus gave grape juice, fish and bread to 5000 people on a Friday and the Islamic day for prayer is Friday. Everyone is Adam and eve's children and we will come together as one when Jesus descends upon the earth in Jerusalem to fight and kill the False Prophet (Dajjal). So why my brothers and sisters are we not coming together as one, as the prophets pbuh ummah (nation). Instead we choose to be ignorant and blind with hatred that we cannot come together as one nation.
The prophet pbuh also stated that the devil will rise between Egypt and Iraq which is Syria and will rise and call himself Muslim and cause destruction on the earth which is happening so why don’t we rise as one nation. Regardless of race or religion. And be one ummah as we are all created from the greatest, most gracious creator of all Allah(god).
Ummah means all people alive, and future people when the prophet is ordered to preach.
It was reported from Abu Hurayrah that the Messenger of Allaah (peace and blessings of Allaah be upon him) said: “By the One is Whose hand is the soul of Muhammad, not one of this nation, Jew or Christian, will hear of me and will die without having believed in that with which I have been sent, but he will be one of the dwellers of Hell fire.”
(Narrated by Muslim, 153)
So every non Muslim and Muslim after 612 CE who died or will die is among the nation of last prophet.
Ummah means group of people believing in Same basics, but the way every/anyone one acts or behaves may be different or even hostile to one another but basics remain same that's to say we all sects Believe in oneness of Allah, messengers, Holy books, angels and here in after life and practice Namaz (salah) with different ways but skeleton is same that's why we can say we are one Ummah with 4 to 7% difference that can be ignored. First thing is to think about primary things that all sects with a little difference believe in..... When we start to practice primary/ basic things like Roza, zakat, namaz, haj etc. and husne ikhlaque we will have no time to think about 4 to 7% difference. Practically we Muslims must try to become one Ummah and we are Alhammadulillah. Thanks