What's the difference between a Masonite door and a steel door?

The difference between a Masonite door and a steel door is that Masonite is a brand that makes many door types including steel, fiberglass, and interior molded doors, while steel door refers to material type, so Masonite can make steel doors and also other types. Masonite International makes steel entry doors as one of its product lines, so a Masonite door can be a steel door if you choose Masonite steel series. However, when comparing Masonite interior molded doors versus steel entry doors generally, differences include material, use, and cost. Masonite interior doors are typically molded wood composite with hollow or solid core for interior use, costing 50 to 200 dollars, lightweight, and not suitable for exterior due to lack of weather resistance. Steel entry doors, including Masonite steel entry doors and steel doors from other brands like JELD-WEN, are made from steel skins with foam core for exterior use, offering strong security, good energy efficiency, and weather resistance, costing 200 to 500 dollars pre-hung, thickness 1-3/4 inches. Masonite steel doors are solid with foam core, while Masonite interior doors are thinner at 1-3/8 inches and may be hollow. So Masonite door is brand, steel door is material, and Masonite makes steel doors as well as other types, with main difference being interior versus exterior use and material construction.