The term 'Bristle Plant' refers to a type of grass that is characterized by its stiff, sharp-pointed awns and bristly seed heads. The scientific name for this plant is Setaria, which is a four-letter word. The awns of the plant are three letters long and are called 'AWN'. The bristly seed heads are known as 'ARISTA', which is a six-letter word. This type of grass is commonly found in temperate regions and is used for grazing and hay production.