始终 is an adverb meaning 'from beginning to end' or 'always,' emphasizing unwavering consistency over time. Literally, 始 means 'beginning' and 终 means 'end' — together they form a compact expression of continuity without interruption. It often conveys persistence, loyalty, or unchanging attitude or behavior across a period, whether short or long.

This word is commonly used in both spoken and written Chinese, especially in formal contexts or when highlighting steadfastness — for example, in describing dedication to a principle, loyalty to a person, or consistent effort despite challenges. Unlike some time-related adverbs, 始终 does not indicate duration (e.g., 'for three hours') but rather the uninterrupted span between two points: start and finish. It typically precedes the verb it modifies and cannot stand alone as a sentence element.