Dictionary merging in Python is a mechanism defined by the aggregation of key-value pairs where overlapping keys result in the retention of values from the second operand, functionally analogous to the set union operation. The core principles governing this process include semantic preservation of custom mapping types versus the default instantiation of the built-in dictionary class, and the precedence rules that dictate value resolution in the event of key collisions. This concept operates within the domain of imperative programming language semantics, specifically focusing on data structure manipulation and the behavioral contracts of specific operators like the pipe symbol and double-star unpacking.
Prerequisite chain context: requires Set Union and Intersection Operations.