Give a brief definition of POS Tagger.

A Part-of-Speech (POS) Tagger is a natural language processing tool that automatically assigns grammatical categories or parts of speech (e.g., noun, verb, adjective) to words in a text based on their syntactic and semantic context. The POS tagger analyzes the linguistic features of each word, such as its morphology, surrounding words, and grammatical structure, to determine its appropriate part of speech label. POS tagging is an essential task in various NLP applications, including text analysis, information retrieval, machine translation, and sentiment analysis, as it helps in understanding the grammatical structure and meaning of text data.