The medium is the means by which ink, pigment or color are delivered onto the drawing surface. Most drawing media are either dry (e.g. graphite, charcoal, pastels, Conté, silverpoint), or use a fluid solvent or carrier (marker, pen and ink).
Watercolor pencils can be used dry like ordinary pencils, then moistened with a wet brush to get various painterly effects. Very rarely, artists have drawn with (usually decoded) invisible ink. Metalpoint drawing usually employs either of two metals: silver or lead.
More rarely used are gold, platinum, copper, brass, bronze, and tinpoint.