Some friends and I were discussing hotels and apartment buildings called "The X Arms" where X is some noun, for example, the Rex Arms apartments, which I drove past today, and we have some questions. Why arms? As in coat of arms? Rex's coat of arms? And why does the name have a connotation of seediness, as several people suggested?

My guess is that there was an original famous place called the X Arms, where X was an aristocratic family name. The formula was copied by people who didn't really get the coat of arms thing and thought "arms" meant fancy hotel. I'm also guessing that the reputation for seediness is because all the Arms were build around the same time, or within a few decades of each other, in similar parts of town. These areas, once posh, eventually deteriorated but the Arms remained and subsequent generations associated the name with flop houses rather than grand hotels.

It certainly isn't the case that there is a connotation of seediness over here. The Something Arms is one of the commonest forms of pub name in the country. There are literally thousands of Kings Arms and Queens Arms for example and many, many others. They represent all standards of pub from squalid dives to top of the market hotels.

Many of these are very old establishments and it seems very likely that the stylke of naming was simply taken to America by colonists and its use perhaps altered. (For example, you mention apartment buildings. We don't really have your condominium style housing over here but it would be extremely unusual for anything other than a pub to get this kind of name.)

Off topic pun...

In Futurama, Bender (the robot) lives at the "Robot Arms apartment building".