Written a new paragraph for var naming recommendation (#7531)

docs/markdown/Style-guide.md

@@ -13,9 +13,12 @@ Always spaces.
 
 ## Naming Variable
 
-The most consistent naming convention is the snake case. Let say you would
-like to refer to your executable so something like `my_exe` would work or
-just `exe`.
+Snake case (stylized as `snake_case`) refers to the style of writing in which
+each space is replaced by an underscore (`_`) character, and the first letter of
+each word written in lowercase. It is the most common naming convention used
+in Meson build scripts as identifiers for variable.
+
+Let say you would like to refer to your executable so something like `my_exe`.
 
 ## Naming options