1. 
   W 18
   W 18 is a cultivated variety of potato.
   Found op http://www.probertencyclopaedia.com/browse/QW.HTM
   
   
2. 
   W-8
   Certificate of Foreign Status form required by the IRS to tell the payer, transfer agent, broker or other middleman that an employee is a nonresident alien or foreign entity that is not subject to U.S. tax reporting or backup withholding rules.
   Found op http://www.duke.edu/~charvey/Classes/wpg/bfglosw.htm
   
   
3. 
   W8
   Wait
   Found op http://www.netlingo.com/acronyms.php
   
   
4. 
   W98
   Windows 98, details ...
   Found op http://www.cryer.co.uk/glossary/w/index.htm
   
   

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