The word 房子 is formed by combining the character 房, which pictographically represents a household or building (originally depicting a door under a roof), with the character 子, which here serves not as a meaning of "child" but as a common, neutral suffix. This suffix 子 attaches to the core concept (房 - building) to form a concrete, everyday noun, giving the word a more colloquial and specific feel, essentially turning the abstract idea of a "building" into the familiar, tangible object of a "house".