While 系列 (xìliè) is a modern, practical term without deep philosophical roots, its usage highlights a key difference in categorization between Chinese and English. In English, we often use distinct words for different types of series: a “book series,” a “product line,” a “fashion collection,” or a “lecture series.” Chinese uses 系列 as a versatile umbrella term that covers almost all of these contexts. A new line of smartphones is a 手机系列 (shǒujī xìliè), and the Harry Potter books are a 图书系列 (túshū xìliè). This demonstrates a tendency in modern Mandarin to use powerful, broadly applicable terms. Instead of learning multiple specific words, a learner can master 系列 and apply it across various domains, from entertainment and commerce to academia. It's less about a unique cultural value and more about the efficient, logical structure of modern Chinese vocabulary.
系列 is an extremely common word used in both formal and informal settings.
Its connotation is neutral; the value (good or bad) depends entirely on the context.