Filament is the plastic that you feed your 3D printer to create unique designs and prototypes. Each 3D printer is different in the diameter and type of filament that its extruder uses. ABS and PLA are the standard filament materials.
What's the difference? ABS is petroleum-based, tough and impact resistant, and melts at higher temperatures (225-250C). PLA is bio-based and is generally made with corn, has a lower melting point (190-240C), and is slightly more brittle.