Information Retrieval (IR) is the process of obtaining relevant documents or data from a collection based on a user's query. It involves searching through vast datasets, typically unstructured data, to find and rank items based on their relevance to the input query.
IR systems use various methods such as keyword matching, semantic search, machine learning, and ranking algorithms to retrieve documents. Examples of IR applications include search engines, recommendation systems, and digital libraries.
The goal of IR is to help users quickly find the most relevant information, making it essential in fields like web search, e-commerce, academic research, and multimedia retrieval.