The word "吃饭" is formed through the straightforward combination of the verb "吃" (to eat) with its most common and fundamental object "饭" (cooked rice, or more broadly, a meal). This pairing creates a concrete, action-object compound that, through constant daily use and cultural centrality, has come to represent the entire, essential concept of consuming a meal. It functions as a single, fused unit where the specific parts together evoke a generalized, whole activity integral to daily life.