The word 镜子 (jìngzi) for "mirror" is formed by combining the core character 镜, which historically denotes the reflective object itself (originally made of polished bronze, hinted by its "metal" radical), with the suffix 子. This addition of 子 does not change the core meaning but transforms it into a more common, concrete, and everyday noun, softening the term and making it the standard, colloquial word for the household item, as opposed to the more technical or classical standalone 镜.