Kuba Szostak in your example if you switch to require instead of define it works. Define is for defining a new module. In the example you provided require, which loads existing modules, will work.
If you want to define a new module take a look at the Write a class help topic which shows how to create the module and load it into your app.
Revised version of your code:
<!DOCTYPE html>
<html>
<head>
<title>Create a Map</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="viewport" content="initial-scale=1, maximum-scale=1,user-scalable=no">
<link rel="stylesheet" href="http://js.arcgis.com/3.13/dijit/themes/claro/claro.css">
<link rel="stylesheet" href="http://js.arcgis.com/3.13/esri/css/esri.css">
<style>
html, body, #mapDiv { padding: 0; margin: 0; height: 100%; }
</style>
<script src="http://js.arcgis.com/3.13/"></script>
<script>
var map;
//require(["esri/map", "dojo/domReady!"], function(Map) {
// map = new Map("mapDiv", {
// center: [-56.049, 38.485],
// zoom: 3,
// basemap: "streets"
// });
//});
</script>
<script>
require([
"dojo/ready", "dojo/on", "dojo/dom-construct",
"esri/config", "esri/map", "esri/graphic", "esri/symbols/PictureMarkerSymbol",
"esri/layers/WMSLayer", "esri/geometry/Extent", "esri/geometry/Point",
"esri/geometry/webMercatorUtils", "esri/InfoTemplate", "esri/dijit/InfoWindowLite"],
function () {
console.log("dojo initialized.");
});
</script>
</head>
<body class="claro">
<div id="mapDiv"></div>
</body>
</html>