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 assigning these tags, computers can better understand the structure and meaning of sentences, which is essential for various applications like text analysis and machine translation. This tagging is typically performed using algorithms that analyze the context of each word within a sentence. Machine Learning techniques are often employed to improve accuracy, allowing systems to learn from large datasets and make informed predictions about word categories in new texts.