What is OData?

I was always confuse between OData and RESTFul API. After few hours of googling, I found below info. 

Definition 
OData (Open Data Protocol) is a protocol which allow to creates and consume querable and interoperable RESTful API in a SIMPLE and STANDARD way. In short, OData consume RESTFul API and allow developer to focus only on their business logic rather than focusing on details of request/respond like type of request, methods, header, URL & Media type etc.

OData VS RESTFul Service?
OData talks about "what" the messages look like (the content). REST is the architecture of "how "those messages get sent back and forth.

OData support operations above CRUD. OData also specifies a very rich query language to enable consumers query your services for precise information they are looking for - with the help of $filter, $orderby, $skip, $top, $expand.

OData helps you describe your entire Data Model - Entities and their Relationships and support all kinds of operations like CREATE, UPDATE, DELETE, GET, MERGE and even CUSTOM OPERATIONS on these Entities and/or Relationships.