The word 一早 is formed by directly combining the character 一 (yī), meaning "one", with the character 早 (zǎo), meaning "early". This creates a literal, conceptual fusion where "one" intensifies or specifies "early", pictorially evoking the idea of the first point or the very beginning of the morning period. It’s a compact, metaphorical construction where the numeral doesn't indicate a quantity but instead emphasizes the initial and foremost part of the time frame represented by "early".