Spoken Dates vs. Written Dates: One of the most important cultural nuances of 号 is its use for dates. In spoken, everyday Chinese, people almost always use 号 to refer to the day of the month (e.g., “今天几号?” - “What's the date today?”). This is the colloquial standard. Its counterpart,
日 (rì), means the same thing but is used in formal, written contexts like news headlines, official documents, and expiration dates.