The frame  is the structure of the printer. It helps hold the extruder head, and acts as a base for the printer bed.

The extruder  is the heart of the printer. It is where the filament is loaded into, where the filament melts, and similar to the name, where the filament is extruded. Much like the printer bed, the extruder head can move on any of the three axises.

The bed  is what the object is printed on. Usually lined with a non-stick sticker, the printer bed can move on the X, Y, and Z axises, but that varies depending on the printer.

The filament  is the material that is extruded. Normally PLA                   (Polylactic Acid) or ABS (Acrylonitrile Butadiene Styrene) is the type of plastic that is melted into the filament. Our entire idea is centered around filament.