Part-of-Speech Tagging is a process in natural language processing that involves identifying and labeling the grammatical categories of words in a sentence. These categories include nouns, verbs, adjectives, adverbs, and more. By tagging each word, computers can better understand the structure and meaning of sentences, which is essential for various applications like text analysis and machine translation. This technique typically uses algorithms and linguistic rules to assign tags based on the context in which words appear. Accurate part-of-speech tags help improve the performance of other language processing tasks, such as named entity recognition and sentiment analysis.