Plastic arts is a term, now largely forgotten, encompassing art forms which involve physical manipulation of a plastic medium by moulding or modeling such as sculpture or ceramics. The term has also been applied more broadly to all the visual (non-literary, non-musical) arts.

Materials that can be carved or shaped, such as stone or wood, concrete or steel, have also been included in the narrower definition, since, with appropriate tools, such materials are also capable of modulation.^{[citation needed]} This use of the term "plastic" in the arts should not be confused with Piet Mondrian's use, nor with the movement he termed, in French and English, "Neoplasticism."

plastic art:
  1 : art (as sculpture or bas-relief) characterized by modeling : three-dimensional art
  2 : visual art (as painting, sculpture, or film) especially as distinguished from art that is written (as poetry or music) —often used in plural

Therefore, it is safe to say that plastic arts in the narrower sense are those visual arts that involve the use of materials such as clay or plaster, that can be moulded or modulated in some way, often in three dimensions.