A single computer instruction that results in a series of instructions in machine language.
1. In applications, a set of keystrokes and instructions recorded and saved under a short key code or macro name. When the key code is typed or the macro name is used, the program carries out the instructions of the macro. Users can create a macro to save time by replacing an often-used, sometimes lengthy, series of strokes with a shorter version.
2. In programming languages, such as C or assembly language, a name that defines a set of instructions that are substituted for the macro name wherever the name appears in a program (a process called macro expansion) when the program is compiled or assembled. Macros are similar to functions in that they can take arguments and in that they are calls to lengthier sets of instructions. Unlike functions, macros are replaced by the actual instructions they represent when the program is prepared for execution; function instructions are copied into a program only once. Compare function (definition 2).
In computer programming, a new command created by combining a number of existing ones. For example, if a programming language has separate commands for obtaining data from the keyboard and for displaying data on the screen, the programmer might create a macro that performs both these tasks with one command. A macro key on the keyboard combines the effects of pressing several individual keys.

(Combining form) Very large in scale or scope or capability
A prefix meaning on a very large scale, as opposed to micro.

1. Being large, thick, or exceptionally prominent
2. Of, involving, or intended for use with relatively large quantities or on a large scale; of or relating to macroeconomics
3. Gross
4. Of or relating to a macro lens or to close-up photography