 Compounds, like other constituents, can be defined as consisting of a head and a non-head. While the non-head or modifier is peripheral to the construction, the head determines several grammatical properties of the compound, such as the number of the compound, for example the plural form, or the gender of the compound indicated by the choice of the relative pronoun, and last but not least, the word class. As we can see here, present-day English has both right-headed and left-headed compounds. However, the vast majority are right-headed. Let us now see in what way the head influences the meaning of a compound. Well, in schoolboy and mother-in-law, the grammatical head also defines the meaning and establishes a hyponymy relationship with the compound. A schoolboy is a type of boy and a mother-in-law a type of mother. If such a relationship can be established, the compound is referred to as endocentric. If the head fails to define the meaning of its compound, such as in pickpocket and redskin, where neither pickpocket is a type of pocket nor is redskin a type of skin, we have an exocentric compound. And if both the head and its modifier contribute to define the meaning of a compound, then we refer to the compound as copulative, as in fighter-bomber, where we have both a fighter and a bomber. So the grammatical head can be used to define three types of compound, endocentric, exocentric and copulative.