| seam [sēm] ENGINEERING 1. A mechanical or welded joint. 2. A mark on ceramic or glassware where matching mold parts join.A line occurring on a molded or laminated piece of plastic material that differs in appearance from the rest of the surface and is caused by a parting of the mold. Also known as mold seam. GEOLOGY 1. A stratum or bed of coal or other mineral. 2. A thin layer or stratum of rock. 3. A very narrow coal vein. METALLURGY An unwelded fold or lap which appears as a crack on the surface of a casting or wrought product. |