For this reason, jurists interpret oaths according to what the person addressed understands in his own language, even if the expression is also used literally of other things. Thus, if someone swears not to eat heads, this may mean the heads of livestock, the heads of sheep and goats, or the kinds of heads customarily eaten. Likewise, the word “eggs” means the eggs familiar to them. The heads of ants, fleas, and the like do not fall within the expression, nor do fish eggs fall within the oath, even though “ants’ eggs” and “fish eggs” are literal expressions when used in these possessive constructions.

Similarly, if someone says, “I have sold it to you for ten dirhams or dinars,” the unqualified wording refers to what people understand that expression to denote in such a transaction in that locality. Indeed, even within a single locality, “dinar” may mean pure gold when pricing certain goods, debased gold when pricing others, and a particular sum of dirhams when pricing still others. By the unanimous agreement of the jurists, an unqualified contract is therefore interpreted according to the shared understanding of buyer and seller, even though the expression is used in other senses only with something that clarifies its meaning.

How much more so, then, when the expressions themselves differ, as with “the back of a human being” and “the back of the road”; “the head of a human being,” “the head of a lane,” “the head of wealth” (capital), or “the head of a spring” (its source)? Or when one expression is qualified by the definite article, as in “the back,” while the other is qualified by a possessive construction? The definite article indicates what is familiar to the person addressed, whereas the possessive construction specifies the referent through its relation to the noun that follows. Thus, an expression made definite by the definite article is not the same as one made definite by a possessive construction, either in wording or in meaning.