1. 
   tab key
   [n] - the key on an electric typewriter that causes a tabulation
   Found op http://www.webdictionary.co.uk/definition.php?query=tab%20key
   
   
2. 
   tab key
   noun the key on a typewriter or a word processor that causes a tabulation
   Found op http://wordnetweb.princeton.edu/perl/webwn?s=tab%20key
   
   
3. 
   Tab key
   Tab key (abbreviation of tabulator key or tabular key) on a keyboard is used to advance the cursor to the next tab stop. The word tab derives from the word tabulate, which means "to arrange data in a tabular, or table, form". When a person wanted to type a table (of numbers or text) on a typewriter...
   Found op http://en.wikipedia.org/wiki/Tab_key
   
   
4. 
   tabkey
   1) It's just left of q
   Found op http://www.mijnwoordenboek.nl/EN/crossword-dictionary/tabkey/1
   
   

Tip: double click on a word to show its meaning.