Infill
Infill is the internal lattice structure printed inside a 3D object to give it strength without filling it completely solid.
Infill is the partially hollow pattern printed inside a model's outer walls. Expressed as a percentage, it trades material, weight, and print time against strength: more infill makes a part stronger and heavier.
Most functional prints do not need to be solid. A moderate infill gives plenty of strength while saving filament and time, which is why infill is one of the most important slicer settings to tune.
Slicer
A slicer is software that converts a 3D model into the layer-by-layer instructions a 3D printer follows to build the object.
Layer height
Layer height is the thickness of each printed layer, which controls the trade-off between surface detail and print time.
Filament
Filament is the spooled thermoplastic material that an FDM 3D printer melts and extrudes to build objects.
Put Infill to work this week.
Knowing the term is step one. The business kits ship the systems and templates that turn concepts like this into a running operation.