"Size is not a document" is a popular expression used in situations where the intention is not to underestimate the quality of something or someone just for its size.
Usually, the expression "size is not a document" is used to refer to people with short stature and who, for this reason, suffer from bullying. Thus, this phrase works as an argument in favor of short people, as it represents the indifference of size in relation to the quality of the individual's characteristics.
However, this expression is usually more common among Brazilians to refer to the male sex organ size. The justification lies in the fact that the size of the penis is not directly proportional to the ability that its bearer has to provide pleasure to his partner (a).
The meaning of this expression is to make it clear that being small is not always synonymous with being weak or inferior. For example, the phrase "if size were a document, giraffe was king of the jungle", shows that the giraffe is one of the tallest animals in the world, however the one known as the king of the jungle is the lion, who is stronger, faster, agile, and famous for his hunting skills.
In short, “Size is not a document” is to show people that what matters is not the appearance, but the qualities, attitudes and abilities of the individual.
To learn more about the meaning of other popular expressions, Click here.