- FDM
- Fused Deposition Modeling — the melt-and-stack-layers method this whole guide is about. The most common home printing type.
- Filament
- The plastic "string" on a spool that feeds into the printer. Usually 1.75 mm thick.
- Slicer
- Software that converts a 3D model into layer-by-layer printer instructions.
- G-code
- The plain-text file of instructions the slicer produces — every move, temperature, and speed the printer follows.
- STL
- The most common 3D model file format. It describes a shape as a mesh of triangles.
- Layer height
- How thick each printed layer is. Smaller numbers look smoother but take longer.
- Infill
- The internal honeycomb that fills the inside of a print. More infill = stronger and heavier.
- Nozzle
- The brass tip that melts and squirts the plastic. Usually 0.4 mm wide.
- Hot end
- The heated assembly that melts filament, ending in the nozzle.
- Extruder
- The motor and gear that push filament into the hot end.
- Bed
- The flat surface a print is built on. Often heated to help parts stick.
- Brim / Raft / Skirt
- Extra plastic around the base. A skirt primes the nozzle, a brim grips the bed, a raft is a full base layer underneath.
- Supports
- Removable scaffolding the printer adds under steep overhangs so plastic isn't printed into thin air.
- Overhang
- Any part of a model that juts out over empty space. Past ~45° it usually needs support.
- Retraction
- Pulling filament back slightly during travel moves to stop oozing and stringing.
- Stringing
- Thin wispy hairs left between parts of a print. Usually fixed with retraction or a lower temp.
- Warping
- When corners lift off the bed as plastic cools and shrinks. More common with ABS than PLA.
- Vase mode
- Printing a single continuous spiralling wall — fast, seamless, hollow. Great for cups and vases.