The word 时刻 is formed by combining two characters that each relate to time, creating a layered, metaphorical concept. 时 broadly means "time", "hour", or "season", representing the general flow or period. 刻 originally refers to a "notch" or "carving", and by extension, a precise "moment" or "quarter-hour", evoking the idea of a marked, specific point. Together, they form a compound where the first character sets the general domain (time) and the second sharpens it into the idea of defined, exact, or significant points within that continuum, much like notches on a timeline.