A Macro is a short programme which automates several steps in a process and can be executed as a single command.
Macros will often replace tedious day-to-day processes, thereby reducing the risk of human error and increasing efficiency.
Macros can be application specific i.e. written into Spreadsheets, Word Processing documents, Databases and CAD scripts, or they can be general i.e. linked to a key or keys on the keyboard.
e.g. a general, keyboard Macro called "User" or even "U" could be used to log a user into a system. The Macro file would hold all the steps required to do this but login could be effected by pressing just one key on the keyboard.