What is a representation of a certain item, often shown as a letter, abbreviation, or sketch?

A symbol serves as a representation of a certain item by using a letter, abbreviation, or a sketch to convey meaning in a concise manner. In electrical contexts, symbols are crucial for illustrating various components and functions within diagrams, making them universally understandable. For instance, specific symbols are used to represent resistors, capacitors, or power sources in schematic diagrams, allowing anyone familiar with these symbols to quickly interpret the intended design or circuit.

Diagrams, while related, are broader graphic representations and may include various components and relationships apart from just the symbolic representation. References are typically used to guide users to specific sources or additional information rather than representing an item directly. Labels serve to provide information or identify objects or components but do not inherently represent the item in an abstract or shorthand form in the way that a symbol does. Thus, the choice of 'symbol' accurately captures the essence of the question regarding representation.