A macro in computer science is a rule or pattern that specifies how a certain input sequence should be mapped to a certain output sequence according to defined rules and procedures. Consider using [vba] tag instead of this one if the question concerns a Microsoft Office product. This helps the people answering, filter questions more efficiently.
Macros refer to any sequence of events that can be programmed to execute without user interaction. There are subsets of macro types that are more specific to the program(s).