Fimbriation is also an armorial term. In describing a "coat of arms" there are several colors (technically "tinctures") referred to, two of which are referred to as metals (silver and gold, i.e., argent and or) and five colors (red, blue, green, purple and black, i.e., gules, azure, vert, purpure and sable). It is not permited to have a metal on a metal or a color on a color, so, if fate decrees that this happen, a thin border of the other (i.e., metal separating colors or color separating metals) is added to the design. This thin border is called fimbriation. The Cubs' baseball cap could be described as azure a block letter C gules, fimbriated argent.