+A4d denotes a specific iteration, often the fourth major revision within a structured [design sequence](/wiki/Design_sequence). It signifies a refined version, built upon earlier principles to achieve a particular objective or [functional enhancement](/wiki/Functional_enhancement). This designation marks a clear step in a methodical progression.
+## See also
+- [Iteration](/wiki/Iteration)
+- [Version](/wiki/Version)
+- [Development](/wiki/Development)
... 1 more lines