TF-IDF (Term Frequency–Inverse Document Frequency) is a numerical statistic used in information retrieval and text mining to measure the importance of a term within a document or a corpus. It quantifies the relevance of a term by considering the frequency of its occurrence in a document, while also accounting for its rarity across all documents. The higher the TF-IDF value of a term, the more significant it is in representing the content of a document.