This article can help you identify the meaning of a macro in Microsoft Word, and understand its use.
A macro is essentially a way to "assign" multiple commands in Microsoft Word to a singular hotkey. In general macros are used primarily to streamline your workload in Word, by allowing you to map the tools or specific formatting options, you use frequently, to one or many hotkeys.
Example: when you're working on a document that you find yourself using the Bold and the Italic function to highlight parts of a paragraph. By default those are two separate keyboard shortcuts, CTRL+B for Bold and CTRL+I for italic. Microsoft Word allows you to combine those two shortcuts into one with the use of a macro.
How it works is, Word give yous the ability to "record" commands into a macro, essentially mapping multiple keyboard shortcuts into one. So instead of using CTRL+B and then CTRL+I separately to make something bold italic, you can map those two commands to something like ALT+CTRL+B by using macros in Microsoft Word.
NOTE: You can learn more on how to create a macro in Word, here.
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