request is a generic way of referring to the subject, we can use the translation that will be as well or better understood as an information request to the server. There are several ways to make a request. The term could be used in other contexts and be the same thing, it has no specific meaning in technology, it is just a word needed to give understanding to what is being used. In this context it is a request using HTTP.

In HTTP, among the various forms of requesting, has the verb used to request it. Each verb has its own semantics to function. One of these verbs is POST . So this term is a very specific form, with proper rules of how to make the requisition. So this is a term with technical meaning defined in the specification.

I've given a answer by differentiating between POST and PUT which shows the main details of POST .

Have another one with basic information about other verbs . And the importance of using the correct verbs . All of these verbs are requisition methods .

You can better understand all this work in the CGI question .

Supplemented the response with an example in PHP .

POST

From post , you create the entire form structure necessary for the operation of web applications. With it you can get the data of a certain field:

<FORM NAME=”form1″ METHOD=”post” ACTION=”pagina.php”>
   Campo 1:
   <INPUT TYPE=”text” NAME=”campo1″>
   <BR>
   Campo 2:
   <TEXTAREA NAME=”campo2″></TEXTAREA>
   <BR>
   <INPUT TYPE=”submit” VALUE=”Enviar”>
</FORM>

<?php
   echo(“O valor do primeiro campo é ” . $_POST[‘campo1’]);
   echo(“O valor do segundo campo ” . $_POST[‘campo2’]);
?>

REQUEST

$_REQUEST , by default, contains the contents of $_GET , $_POST and $_COOKIE . It is called a generic collection, because it returns the value of the variable, according to the configuration of the file php.ini :

<FORM NAME=”form1″ METHOD=”post” ACTION=”pagina.php?x=1″>
   <INPUT TYPE=”text” NAME=”txtCampo1″ VALUE=”Valor do Campo Texto”>
   <INPUT TYPE=”submit” VALUE=”Enviar”>
</FORM>

<?php
   echo($_REQUEST[‘v’]);
?>

See this answer for stackoverflow in English.

References:

• Difference between GET and POST methods
• GET, POST, REQUEST