Wife beater

Being taught British English in school, I sometimes get confused with American expressions. One quite funny situation occurred a few weeks ago when a friend of mine during a dinner said that he had to leave early to go and buy a wife beater. Since I know this person quite well, or at least thought I did, I got shocked and didn't really know what to say. Furthermore, I also found it strange that none of the others around the table said anything.

When I heard the word "wife beater", I thought it was a tool to hit people with. Luckily one of my friends had heard the expression before and asked the American students around the table why they called it a wife beater. It was explained to me that a wife beater is another word for a sleeveless shirt, and that the expression probably came from wife abusers in movies who often wore those kind of shirts. Personally, I think it is a very strange name and I believe that there are more people like me who get confused when hearing it.