Is there a Poker etymological dictionary out there that explains the origin/history of the poker terms? There are many terms in Poker with meanings that are not immediately obvious and it'd be nice to find out their origins, for example terms such as cow, broadway, cooler, coffee housing, come bet/betting on the come, etc...
Personally I like this site: http://pokerterms.com/
It does answer your cow question (and many others): http://pokerterms.com/cow.html
This is good too: http://www.poker1.com/archives/2344/wiesenberg-official-dictionary-of-poker-mcu-intro but has a drawback: When you search you have to search the whole site, not only the dictionary
Some of the terms are defined here: http://en.wikipedia.org/wiki/Glossary_of_poker_terms.
Some etymology here: http://www.flopturnriver.com/top-10-poker-lingo.php