Definition of "NG"

(petrochemistry) Initialism of natural gas.  examples

Initialism of nitroglycerin.  examples

(Internet) Initialism of newsgroup.  examples

(rail transport) Initialism of narrow gauge.  examples

Not OK. Initialism of no good.  examples

Initialism of nasogastric.  examples

(Internet) Initialism of Newgrounds.  examples

Initialism of National Geographic.  examples