The word "牌子" is formed through the combination of two characters: "牌", which originally refers to a flat, placard-like object such as a signboard, tablet, or label used for identification or display; and "子", a very common nominal suffix that, when attached, often signifies a concrete, smaller, or more familiar version of the root concept. Together, they create a compound that conceptually extends from a physical sign or plaque to encompass anything that serves as a marker of identity, brand, or make, metaphorically carrying the function of the original "牌" into abstract realms like commercial branding or reputation.