Nach Google Bilder von "rump steak" ist es genau unser "Rumpsteak".

support Me: you won't find 'rump steak' on any menu in NA, it ususally makes people laugh because of rump = Gesaess. Might be different in England, although I had this conversation with some British friends before (no scientific proof, I know...) and they weren't familiar with the term either.

That's the way I see it. I have never seen a "rump steak" on any menu in NA. Probably the cut of the beef is just different. I agree that sirlion comes the closest to it.
But hey, I'm no butcher. I jsut love steaks!

Rump steak sounds fine to me, from the UK, and the dictionaries say it exists:

rump noun 3 (also rump steak) a cut of beef from the rump.
(Chambers)

rump /rmp/ noun
2 [U] (also rump steak [C, U]) a piece of good quality meat cut from the rump of a cow
(OALD)

rump
2 : a cut of meat (as beef) between the loin and round http://www.merriam-webster.com/dictionary/rump

rump
A cut of beef or veal from the rump.
The American Heritage ® Dictionary of the English Language, Fourth Edition

rump steak
a steak cut from the rump
http://www.wordnet.princeton.edu/perl/webwn

Diagram of meat cuts including rump (UK) http://www.beefyandlamby.co.uk/cuts/cuts_beef.html

Sirloin does not seem to be the same as rump:

sirloin noun a fine cut of beef from the loin or the upper part of the loin.
ETYMOLOGY: 16c: from French surlonge, from sur above + longe loin.
(Chambers)

sir•loin /slIn; NAmE srl/ (also sirloin steak) noun [U, C] good quality beef that is cut from a cow’s back
(OALD)

Collins German Dict
rump (steak) - Rumpsteak
sirloin (Cook.) - Lendenfilet

However, I can't see many US hits for "rump steak" and "menu" on Google, although there are plenty from the UK and Australia. Could it be that the meat is simply cut differently in the US? That even though it is called rump steak, rump steak is not often sold there?

"In beef and pork the sirloin and rump are separate cuts." http://www.boergoats.com/clean/articleads.php...

"Harrods, which began stocking Wagyu beef about 18 months ago, sells American-produced rump for £55 a kilo, sirloin at £79 a kilo and fillet at £89 a kilo." http://www.guardian.co.uk/food/Story/0,2763,1...

I support Archfarchnad -gb-.
I've heard the term before in US usage and I'm no steak lover. Although I do agree with bike_helmut that it is probably not on many US restaurant menus. After all, who wants a steak cut from a cow's ass? Anyway the big US steakhouse chain, Ponderosa/Bonanza does not include "rumpsteak" on their menu. But I have heard it used.

http://www.ponderosasteakhouses.com/menu.htm
somehow this got lost previously

@wpr: "who wants a steak cut from a cow's ass"

In Austria it's the delicacies that come from a cow's ass: Tafelspitz, Scherzerl:
http://www.naturbiotik.at/html/rind.html

das Sirloin Steak wird aus dem Rückensattel des Rindes geschnitten und entspricht dem Kotlett vom Schwein ohne Knochen. In Deutschland wird der Begriff Rumpsteak falsch benutzt! Das "Rump"-Stück ist die Keule des Rindes und wird in Deutschland selten für Steaks verwendet. Die Keule wird verwendet für Rouladen, Gulasch,Schmorrbraten usw. weil das Fleisch zäher ist als das Sirloin- oder Filetstück und länger gekocht werden muss. Das T-Bone Steak ist das Sirloin Steak mit halben Wirbelknochen, Rippenknochen und Filet auf der innenseite des Rippenknochens.