1) In Microsoft Word and other programs, a macro is a saved sequence of command s or keyboard strokes that can be stored and then recalled with a single command or keyboard stroke.
2) In computers, a macro (for "large"; the opposite of "micro") is any programming or user interface that, when used, expands into something larger. The original use for "macro" or "macro definition" was in computer assembler language before higher-level, easier-to-code languages became more common. In assembler language, a macro definition defines how to expand a single language statement or computer instruction into a number of instructions. The macro statement contains the name of the macro definition and usually some variable parameter information. Macros were (and are) useful especially when a sequence of instructions is used a number of times (and possibly by different programmers working on a project). Some pre-compilers also use the macro concept. In general, however, in higher-level languages, any language statement is about as easy to write as an assembler macro statement.
Assembler macros generate instruction s inline with the rest of a program. More elaborate sequences of instructions that are used frequently by more than one program or programmer are encoded in subroutines that can be branched to from or assembled into a program.