Basic process \Ba"sic proc"ess\ (Iron Metal.) A Bessemer or open-hearth steel-making process in which a lining that is basic, or not siliceous, is used, and additions of basic material are made to the molten charge during treatment. Opposed to {acid process}, above. Called also {Thomas process}. Thomas process \Thom"as proc"ess\ (Iron Metal.) Same as {Basic process}, above.