Get a hold of the White Rabbit kanji flashcards if you can. That card is in the first set, as it's pretty commonly used and helpful to learn.
The 'on' yomi is "sei" or "se", while the 'kun' yomi is 'yo'.
The definition in the cards is "world, age, generation", or just use a nice online kanji dictionary, like so:
http://www.saiga-jp.com/cgi-bin/dic.cgi ... 3587_91670
It's the first one listed there.
Good luck!