noun
: a gas used in synthesis ; especially : a mixture composed essentially of hydrogen and carbon monoxide often in a ratio of 2 to 1, produced by various methods (as by the action of steam with or without oxygen on coal or lignite, by the action of steam or oxygen on methane or natural gas, or by enrichment of blue gas with hydrogen), and used chiefly in the synthesis of methanol and ammonia, in the Fischer-Tropsch process, and in the oxo process — compare producer gas