Definition - What does Block Diagram mean?
A Block Diagram is a representation of a system in which the principal parts or functions are represented by blocks connected by lines that show the relationships of the blocks. They are used in engineering in hardware design, electronic design, software design, and process flow diagrams. Block diagrams are typically used for higher level, less detailed descriptions that are intended to clarify overall concepts without concern for the details of implementation.
Petropedia explains Block Diagram
Block diagrams provide a quick, high-level view of a system to rapidly identify points of interest or trouble spots. Because of their high-level perspective, they may not offer the level of detail required for more comprehensive planning or implementation. A block diagram will not show every wire and switch in detail, that's the job of a circuit diagram. A block diagram is especially focused on the input and output of a system. It cares less about what happens getting from input to output. This principle is referred to as black box in engineering whereby the parts that get us from input to output are not known or they are not important.