LINQ (Language Integrated Query) is a Microsoft .NET Framework component that adds native data querying capabilities to .NET languages, including C# . It was originally released as a major part of .NET Framework 3.5 in 2007. LINQ provides a consistent query experience to query objects, relational databases, and XML.

Some key features of LINQ include:

• Query Expressions: These are written in a declarative query syntax and are used to perform filtering, ordering, and grouping operations on data sources with a minimum of code.

• LINQ Providers: These are used to define the different flavors of LINQ, including LINQ to Objects, LINQ to SQL, LINQ to XML, and more.

• Uniform Query Syntax: LINQ provides a uniform query syntax in C# and VB.NET to retrieve data from different sources and formats, eliminating the mismatch between programming languages and databases.

LINQ queries return results as objects, which enables developers to use an object-oriented approach on the result set and not worry about transforming different formats of results into objects.

Overall, LINQ is a powerful set of technologies that provides querying capabilities to .NET languages with a syntax similar to SQL, making it easier for developers to query and transform data from various sources.