To dream about the size of something represents the importance or lack of importance that you attach to certain objects or persons. The larger something is, the more important it is. Conversely, the smaller something is, the more trivial it is. Size also relates the degree of power you are exerting and the power others have on you. Perhaps the dream indicates that you are “sizing” someone up.
According to Freudian school of thought, the size of an object, signifies the size of someone’s penis, perhaps your own or your lover.