GB in WordNet English dictionary

1. a unit of information equal to 1024 mebibytes or 2^30 (1,073,741,824) bytes
   gigabyte  gibibyte  G  GB  GiB 
   
2. a unit of information equal to 1000 megabytes or 10^9 (1,000,000,000) bytes
   gigabyte  G  GB 
   
3. an island comprising England and Scotland and Wales
   Great Britain  GB 
   
4. a highly toxic chemical nerve agent that inhibits the activity of cholinesterase
   sarin  GB