The word 入狱 is formed through a direct, ideographic combination where the first character 入 (rù), meaning "to enter", visually depicts a downward-pointing wedge or arrowhead suggesting movement inward, and is placed before the second character 狱 (yù), meaning "prison", which itself is a complex character historically representing a place of confinement and dispute. Together, they create a simple spatial metaphor: one "enters into" the state or physical location of imprisonment, forming a compound that conceptually captures the action and its immediate, consequential setting in a single, efficient unit.