This process is called overextension and the most common pattern is for the child to overextend the meaning of a word on the basis of similarities of shape,sound and size,and,to a lesser extent,movement and texture. Thus the word ball is extended to all kinds of round objects,including a lampshade,a doorknob and the moon. Or, a tick-tock is initially used for a watch, but can also be used for a bathroom scale with a round dial. On the basis of size,presumably the word fly was first used for the insect and then came to be used for specks of dirt and even crumbs of bread. Apparently due to similarities of texture, the expression sizo was first used by one child for scissors, and then extended to all metal object. The semantic development in a child's use of words is usually a process of overextension initially,followed by a gradual process of narrowing down the application of each term as more words are learned.