Semiconductors are the "chips" that make PC's, iPhones and Set Top Boxes work. Examples include SoCs which are Systems on Chips that accelerate media (e.g., video, graphics and audio) using embedded processors
System-on-a-chip or system on chip (SoC or SOC) refers to integrating all components of a computer or other electronic system into a single integrated circuit (chip). It may contain digital, analog, mixed-signal, and often radio-frequency functions – all on a single chip substrate. A typical application is in the area of embedded systems.
A reference design is a sample board design which can be used to achieve a "design win" with the client. The client can even use customize a reference design into a salable product. Enables rapid development and shows off hardware, software, SDK/utilities, OS Support, etc. (complete BOM)