Advent Wreath Candles. Set on the branches of the wreath are four candles: three purple candles and one pink candle. In the center of the wreath sits a white candle. As a whole, these candles represent the coming of the light of Christ into the world. On the first Sunday of Advent, the first purple candle is lit.
In mathematics,  a coefficient is a multiplicative factor in some term of a polynomial, a series or any expression; it is usually a number, but may be any expression. In the latter case, the variables appearing in the coefficients are often called parameters, and must be clearly distinguished from the other variables.
The coefficient of relationship is a measure of the degree of consanguinity (or biological relationship) between two individuals. The term coefficient of relationship was defined by Sewall Wright in 1922, and was derived from his definition of the coefficient of inbreeding of 1921. The measure is most commonly used in genetics and genealogy.