In the Poaceae family the inconspicuous flowers are gathered in spikelets; each spikelet is subtended by 2 bracts called glumes and every single flower is in turn subtended by 2 further bracts called lemmas:
The spikelets are 1-flowered when they include a single fertile flower:

The spikelets are 2-many-flowered when they include more than one fertile flower: