Powdered green tea is just tea powder made from leaves of tea plants (tea leaves), but its manufacturing process is different from that of green tea for brewing, since powdered green tea is firstly dried after being steamed, then pounded down to eliminate such impurities as the veins of leaves, and further ground by so called "chausu" (a set of millstones for tea leaves.)
抹茶は、有態に言えばチャノキの葉（茶の葉）を粉としたものだが、その製造工程が煎茶とは異なり、蒸すから乾燥させ、これを砕いて葉脈などの不純物を取り除き、さらに茶臼という臼でひいたものである。