Definition – What does OData mean?
Open Data Protocol or just OData is a protocol for the querying and updating of data utilizing existing Web protocols. It is a REST-based protocol built on standardized technologies such as HTTP, XML and JSON. As compared to the other REST-based web services it is different and provides a uniform way to describe both that data and the data model. OData considered being a flexible technology for enabling interoperability between a disparate data source, apps, clients and services.
Glossary Web explains OData
The protocol supports the description of data models and the editing and querying of data according to its models. It provides facilities for data, metadata, editing and operations. The basic idea behind Open Data Protocol is to use a well-known data format to expose a list of entities. AtomPub extends the basic Atom Protocol by allowing not only read but the whole set of CRUD operations. The protocol extends AtomPub by enabling simple queries overfeeds. OData also exposes a collection of data entity sets with a higher-level grouping feed where the user can see all the feeds available.