Frankfurt and Munichy diffderent names?

I would say buy directly from Deutschbahn not Eurorail unless you are doing a ton of back to back to back train travelling.

Ubahn is the subway
Sbahn is the streetcar

ICE is the high speed train. But there are also regional trains between cities.

The many different names you are seeing for Munich and Frankfurt are the different station. It will depend on where you want to go/see.
Hbf is normally the main train station.
Flughafen is the airport

Is it rushed to take train to Rothenburgh from Frankfurt airport
straight away after i check out of Frankfurt airport with the advanced
reservation of train ticket? Upon my arrival in Frankfurt airport, is
it rushed to take train just after i check o

If you ride the REGIONAL trains only after your flight, you should not buy a train ticket in advance. Just go to the ticket machines - or to a ticket window at the airport's REGIONALBAHNHOF station, buy a ticket, and board ANY regional train sequence that day which goes to your destination.

To find a regional train schedule, go to the DB link: https://int.bahn.de/en/

You want to go to Rothenburg, right?

from: Frankfurt (M) Flughafen Regionalbf
to: Rothenburg ob der Tauber

Input your information and click on "mode of transport" - choose "local transport only" to find your itinerary options.

The long-distance trains depart from Frankfurt (M) Flughafen Fernbf station, a 2nd station right at the airport.
Cheaper "saver fares" can be bought online, but they are train/time- specific. If you miss a schduled ICE or other long-distance train, the saver fare ticket is useless. In this case you can buy a ticket at the station for these trains, but the price will be much higher than the saver fare.

If you want to buy a train ticket in Germany, it's best to use DB, www.bahn.de, and not a third party site.

You'll find many options when you search for Frankfurt because there are many stations in the area. The official name of the city is Frankfurt am Main, which is often shortened to Frankfurt (M), Frankfurt a.m. or similar. Hbf is the central station and Flughafens means airport. There are two stations at the airport, the Regionalbahnhof for regional trains and the Fernbahnhof for long distance trains. Those names are often shortened, because "Frankfurt am Main Flughafen Fernbahnhof" can be a bit long.

S-bahn is not a street car. Those are called Strassenbahn.
An S-bahn often travels between near-by towns and cities above ground, but when it comes into a large city, it goes underground. It often travels a longer distance and with fewer stops than an U-bahn.
An U-bahn may also travel between towns, but not as far as an S-bahn. They will also travel above ground until it gets close to the main city where they usually begin or end.

Frankfurt am Main, is the correct name for Frankfurt. The Main is the name of the river and is not to be confused with the English word, main. The German word for main - as in main station, would be Haupt. So the main train station in every city and town is the Hauptbahnhof. Many other stations, may have variations of Bahnhof in their names if they are a major station in one end of town or near a big landmark.
Large cities will have multiple stations. A city like Frankfurt or Munich may have 100s of stations and they may all pop up when you are looking for a travel route.

FRA is the abbreviation for Frankfurt Airport.

Actually, Ms Jo's explanation was very good, but considering she lives in Germany, it should be.

I might add that the U-bahn (Untergrund-Bahn) are smaller, lighter cars and don't run on lines with full-sized trains. All but three U-bahn stations (all have Garching in their name) are within the central, M, zone, so you don't have to worry much about traveling on the U-Bahn and inadvertently going outside your ticketed zone. Also, very few U-Bahn stations are above ground.

The S-Bahn (Schnell-Bahn) cars are bigger and sometimes run on lines with full-sized trains. The S-Bahn runs underground in town, but above ground out into the suburbs to places like the airport, Freising, Gerltendorf, and Herrsching.

Frankfurt (M) Flughafen would not indicate a specific Bahnhof, but would indicate either of the two stations at the airport, , either the Fernbf (for long-distance trains) or the Regionalbf (for Regional trains and S-Bahns).

Actually, Ms Jo's explanation was very good, but considering she lives in Germany, it should be.

why the judgmental attitude?

Lee, if she is in Frankfurt, the U-bahns and their stations are all above ground once they get outside of the city, just like the S-bahns. I would think Munich would be similar.

U-bahns and S-bahns use different tracks too. They do not run on the same tracks or the same platforms in the stations. Not sure why, but size might have something to do with it, like their width. Am not a train person.

Ms. Jo nailed it. Great explanation that also applies well to Hamburg (except a small section on the river, where the U-Bahn is above ground, allowing for a beautiful view of the harbor, but that's a local quirk). S and U Bahn network is along the lines of the NYC Subway--stations everywhere, various intersections, heading into town from various suburbs. Basically a city network for locals who commute from outlying neighborhoods and towns and for people moving within the city. There are differences between U and S as described, but these are not relevant to your journey. These are included in the Deutschland-Ticket.

RB / RE are Regionalbahn and Regional-Express, or trains between towns in the region. These stop at lots of small towns, can be wonderful for scenery, and are included in the Deutschland-Ticket.

IC / ICE (InterCity and InterCity Express) are trains that connect larger cities. The ICE is the high speed train. You generally purchase for a specific train with these, and as someone said, you can get stuck paying double if you miss your pre-booked train.

Hauptbahnhof (Hbf) means central station. Flughafen means airport. Fern means distant, so Fernbahnhof means longer distance trains (not U- or S-Bahn, but trains going further afield). So yes, Frankfurt Flughafen Fernbahnhof makes sense if you are going to Rothenburg o.d.T.

www.bahn.de is the German train website, and most larger stations will have an information counter with someone who speaks English. Also, most Germans, especially younger ones speak English and will have phones, often with the DB app, so you can get advice from a great many places. Germans often look unapproachable, but don't let that deter you.

For public transport (U- and S-Bahn) maps, just google the city name and S-Bahn. You can print off maps if that makes you feel more at ease.

I would simply put Frankfurt Flughafen into the Deutsche Bahn website and select the option that works for you. Most likely it will automatically kick you to the Fernbahnhof, but if the option involves, say, a bus or S-Bahn to Frankfurt's central station, it would show that, too. Then simply click on the connection you want based on times, price, flexibility.

Thanks for all your replies. I really appreciate them so much. I find them very useful and very helpful.

I would like to make double sure to understand correctly. I do not want to make any mistakes. I feel a bit stressed.

1. Frankfurt Rhein Main is actually known as FrankFurt (FRA) and FrankFurt AM, correct? Because the air ticket states FrankFurt Rhein Main terminal 1. I need to book the train tickets in advance in order to travel from Frankfurt to Rothenburg. Actually i am supposed to arrive at Frankfurt Rhein Main airport at 6:35am and check out and board the train from there to Rothenburg at 8:30am. One thing i need to know, how far is Terminal 1 to the ICE or regional train terminal? Is it sufficient to board train at 8:35am which i am thinking to book tickets for 8:35am on that day? Is it rushed or sufficient? Actually, I'm thinking to skip Rothenburg because i feel it is a bit rushed although i badly wanted to visit there. Is it sufficient to take few hours to visit Rothenburg?

I agree with you that ICE is the fastest train. I prefer time saving journey.
I am thinking to use ICE/EC/IC for longer distance like from Berlin to Krakow overnight.

Buy a "Deutschlandticket" cost only eur 54 monthly. Deutschlandticket means we use regional express/slower trains but it requires to stop at every station, correct? Buying that ticket requires the one to book it in few months advance, correct? Can it be used for all European countries? I check and find that S-Bahn and U-Bahn costs Eur $2 or 4 each journey. Single trip costs eur $2-4 while day trip costs eur $10 approximately.

Does it mean that i need to buy Deutschlandticket and ICE ticket?

Any experience with sleeper train? Feel comfortable? Spacious? I google and find that sleeper train seems a bit cramped. I intend to book the sleeper train on two occasions to save accomodation costs.

I heard that Bahn trains are known for the delays. Is it true? I'm thinking to hitch ICE train back to Frankfurt Airport without spending time sightseeing in Frankfurt to go home on the last day but my worries is, i might miss my flight on that last day if there are any delays. I pray that there won't be delays on trains.

The abbreviation for the Airport is FRA. (short for Fraport) The name of the city is Frankfurt am Main, or Frankfurt/Main. It means Frankfurt on the Main River.

The long distance train station is about a 10 min. walk from the arrival gates in Terminal 1.

There are so many towns that are like Rothenburg, that am not sure I would go out of my way to go to them. Your plan sounds stressful to me.

A Deutschland ticket is only valid in Germany. It is valid for the S-bahns and U-bahns.
Personally found the sleeper train to be very uncomfortable. What is the price of the sleeper train compared to a comfortable, budget hotel?

Maybe if we knew why you wanted to visit the places you want to see, we could give you better advice. Who knows, perhaps Frankfurt has the museums or sights you want to see. Perhaps going straight to Munich is better.
Have you looked at round trip tickets to Munich, since you do not want to see Frankfurt or any of the interesting towns around it. Why are you flying here? Now you have the cost and the stress of leaving and getting back here. Added to your jet-lag on arrival day.