The word "往日" (wǎngrì) is formed through the combination of the character "往," meaning "past," "former," or "to go toward," and "日," meaning "day" or "sun." Together, they create a compound noun where "往" acts as a modifier describing the nature of the "日." Literally, it translates to "past days," but it functions as a single lexical unit meaning "former times" or "bygone days," evoking a sense of nostalgia for a time that has gone by. This structure is a common pattern in Chinese where two meaningful characters (morphemes) are combined to produce a new, specific meaning that is related to but distinct from the sum of its parts.