In computing, Open Data Protocol is an open protocol which allows the creation and consumption of queryable and interoperable RESTful APIs in a simple and standard way. Microsoft initiated OData in 2007.
Shortly said, OData is similar to GraphQL, has more history and being used by large companies, when GraphQL is new and used by startup companies.
OData specifies protocol to generate filters, sort data and paginate, similar to SQL languages, also returns links
For example, if you want to get product with specific ID:
https://my-api.com/Products(12345)
If you want to get products with name contains boot:\
https://my-api.com/Products?$filter=contains(name, ‘boot’)