Natural Language Understanding (NLU) is a branch of artificial intelligence that focuses on enabling computers to comprehend and interpret human language. It involves processing text or speech to understand the meaning behind words, phrases, and sentences. NLU helps machines grasp context, intent, and sentiment, making it essential for applications like chatbots and virtual assistants. By utilizing techniques from linguistics and machine learning, NLU allows computers to analyze language patterns and respond appropriately. This technology is crucial for improving user interactions with systems, making communication more natural and efficient. Examples of NLU applications include Siri, Alexa, and customer service automation.