The relationship between two or more similar things in size, number, or degree. The numerator and denominator of every fraction function in this way. For example, "1/2" represents the ratio between one and two: one of two equal parts that together make a whole. 3/6 and 50/100 are similar ratios. Ratios are often expressed as numbers separated by a colon, and read as "is to." Analogies are often made using ratios. An example is 50:100 as 1:2. Ratio is essential to scale and proportion, and to the particular type of proportion known as the Golden Mean.(pr. RAY-shee-oh)