Nouns

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