any of the more than 100 known substances (of which 92 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter
former measure of the United States economy; the total market value of goods and services produced by all citizens and capital during a given period (usually 1 yr)
(orthopedics) the act of pulling on a bone or limb (as in a fracture) to relieve pressure or align parts in a special way during healing; "his leg was in traction for several days"