A Wordlist is a file containing a list of passwords to be tested.  Most of the time, the file is a .txt format or simple text format.  
For KisMAC, the file MUST be .txt with an empty line at the end.
- The empty line is mandatory -
The RockYou List was a password heist of 32 million passwords from the -now- infamous RockYou Website
The size unzipped is 280 MB 
The refined list, statistically speaking, is very interesting and grants you a 5% chance to crack a password in less than 5 sec and 10% in less than one hour.