Designator: a unique identifier for each component on a PCB. These usually take the form of R3, U1, C2, etc.

LSB: Least Significant Bit - the smallest unit of resolution. Generally for an ADC or similar device.

Net: a group of electrically connected points on a PCB. You can also think of a net as a single continuously connected wire in a circuit.

Pad: an area of exposed copper on a PCB where components are soldered to.

PCB: printed circuit board. This refers to the electronic assembly that has positions to electrically connect electronic components.

Pin: the small pieces of metal used to connect components to a PCB. The term ‘pin’ is also used to refer to the small pieces of wire coming off components in their Altium schematic representation.

Pitch: the center-to-center distance between pins on a header.

Silkscreen: white writing on PCBs. Used for labels, designators, pad outlines, etc.

Trace: physical copper strip on a PCB that acts as a wire.

Via: a small hole in a PCB that provides an electrical connection between layers.