Schematic symbols represent electronic devices in schematic diagrams.

 

A schematic symbol consists of one or more symbol terminals, a symbol reference,  a symbol value and associated graphics. The graphics have no electrical significance, they only serve to give you a visual clue as to what the symbol represents. The symbol terminals represent the electrical part of the symbol.

 

The symbols terminals can be visible or invisible on schematics. For instance the NPN transistor below has no visible terminals, only the graphics is visible.

 

 

The PIC micro below has 6 visible terminals as well as graphics. The terminals are the horizontal lines e.g.the line to the right of the VDD text.

 

Schematics symbols are connected together with wires.

 

In addition, a schematic symbol also has a symbol reference and a symbol value.