The word 按时 is formed by combining two individual characters, each contributing its core meaning to create a new, composite idea. The first character, 按 (àn), fundamentally means "to press" or, by extension, "according to" or "based on". The second character, 时 (shí), means "time" or "a set period". When joined, they create a conceptual blend where 按 provides the sense of adherence or alignment, and 时 specifies the object of that adherence. Thus, the formation is a direct semantic fusion: "according to/pressing against" + "time" to express the unified meaning of "on schedule" or "punctually".