毎日

Functions both as a noun and an adverb. When used adverbially, it describes an action performed consistently every single day without exception. When used as a noun, it often modifies another noun (e.g., 毎日の習慣 - daily habit) to describe things pertaining to a daily routine.

While it is often translated as "every day," it can carry a nuance of monotony or boredom depending on the context, such as when describing a repetitive cycle of work and sleep. In such cases, it emphasizes the unchanging nature of the routine.

Compared to the synonym 日々 (hibi), 毎日 is more concrete and focuses on the individual units of days. 日々 is more abstract, often referring to the gradual passage of time or a continuous process of change (e.g., 日々成長する - growing day by day).

Avoid confusing it with 毎日 (Mainichi), the name of the major Japanese newspaper. While the word is the same, the context will clearly distinguish between the frequency of time and the media organization.