The character 对 carries the core idea of facing something directly or aligning with it, while 准 introduces the crucial element of precision, exactness, or hitting a mark. The formation is a conceptual fusion: the first character provides the directional action of orientation, and the second character sharpens that action with the requirement of accuracy. Together, they synthesize into a single concept of actively aligning something precisely with a target or standard, like sighting down a barrel or calibrating a tool, where the notions of "facing" and "exactness" are inseparably merged.