The new home for Visual Studio documentation is Visual Studio 2017 Documentation on docs.microsoft.com.

The latest version of this topic can be found at EQU.

The first directive assigns numeric value of expression to name.

      name EQU expression  
name EQU <text>  

The name cannot be redefined later.

The second directive assigns specified text to name. The name can be assigned a different text later. See TEXTEQU.

Directives Reference