The material with which an artist paints is called the medium. The surface upon which an artist paints is called the support. Some examples of media (the plural of medium) are oil paint, watercolor, egg tempera and fresco. This means that powdered pigments are mixed with oil, water, egg yolk or egg white so that they may be applied to different supports. Some examples of supports are canvas, paper, wood panel and plaster covered masonry or brick wall. Different media require different supports to last or remain stable.

Giotto
"The Betrayal"

Medium: Fresco
Support: Plaster on masonry wall

Hugo van der Goes
"The Portinari Altarpiece"

Medum: Oil paint
Support: Wood panel

Theodor Gericault
"The Raft of the Medusa"

Medium: Oil paint
Support: Canvas