Structure of code blocks - The Org Manual

The structure of code blocks is as follows:

     #+srcname: <name>
     #+begin_src <language> <switches> <header arguments>
       <body>
     #+end_src

code blocks can also be embedded in text as so called inline code blocks as

     src_<language>{<body>}

     src_<language>[<header arguments>]{<body>}

<name>: This name is associated with the code block. This is similar to the ‘#+tblname’ lines that can be used to name tables in Org-mode files. Referencing the name of a code block makes it possible to evaluate the block from other places in the file, other files, or from Org-mode table formulas (see The spreadsheet).
<language>: The language of the code in the block.
<switches>: Switches controlling exportation of the code block (see switches discussion in Literal examples)
<header arguments>: Optional header arguments control many aspects of evaluation, export and tangling of code blocks. See the Header arguments section. Header arguments can also be set on a per-buffer or per-subtree basis using properties.
<body>: The source code.