OPA(redirected from orthophthalaldehyde)
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OPA:see Office of Price AdministrationOffice of Price Administration
(OPA), U.S. federal agency in World War II, established to prevent wartime inflation. The OPA issued (Apr., 1942) a general maximum-price regulation that made prices charged in Mar., 1942, the ceiling prices for most commodities.
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In a classical temple, a cavity which receives a roof beam.