[Lingo] 大新??

[steve smith <sjs@example.com>]

Hi all.

I see things like "大新商品、登場" fairly often.  The "大新" doesn't 
show up in my dictionaries as a word itself but I know what it means by 
it's kanji.  When you encounter something like this, how do you know how 
to pronounce it?  I'm guessing this would probably be だいしん, but how 
would one know?

Thanks
Steve S.