As a Chinese, I always get damn confused when people on screen with a big head of wig start using words like “duchess” “lord”…so here is some quick references. Someday, I may even tackle Shakespeare..lol.

Duke  公爵 duchess
Marquess (or, in the French and Scottish spelling, Marquis) 侯爵
Earl 伯爵 Count
Viscount  子爵
Baron(2) 男爵

Baronets, while holders of hereditary titles, are not peers. Knights, Dames, and holders of other non-hereditary Orders, decorations, and medals of the United Kingdom are also not peers.

House of Lords  （英国国会的）上议院

http://www.chinet.com/~laura/html/titles02.html

http://en.wikipedia.org/wiki/Peerage