1:  an economic good: as
a :  a product of agriculture or mining
b :  an article of commerce especially when delivered for shipment <commodities futures>
c :  a mass-produced unspecialized product <commodity chemicals> <commodity memory chips>

2 a :  something useful or valued <that valuable commodity patience>; also :  thing, entity
b :  convenience, advantage

3 obsolete :  quantity, lot

4:  a good or service whose wide availability typically leads to smaller profit margins and diminishes the importance of factors (as brand name) other than price

5:  one that is subject to ready exchange or exploitation within a market <stars as individuals and as commodities of the film industry — Film Quarterly>