node
DOM element.
Description
When working with the DOM, as is typical in a web-browser using JavaScript(!), you will often assign DOM elements to a variable - we define this as a node for ease of reference. For example:
var node = document.getElementById('example');
Or with jQuery:
var node = $('#example').get(0);
Technically this is an object primitive, but defining such objects as a node allows the documentation to be much more succinct.
Use in DataTables
Where a parameter is shown as accepting a node type, or a method returning a node type, it indicates that an object is expect / returned which refers to a DOM element.
Note that node refers to the native DOM element, not a jQuery object containing the element. Many DataTables methods will accept both a node and a jQuery instance, but this isn't always the case, particularly when considering returned values.