for anyone to do so, since no one can report on the authority of the Arabs that they assigned these expressions to meanings other than those in which they are used.

If they say:

“They did say ‘the bird’s wing’ and ‘the human back,’ and used the words ‘back’ and ‘wing’ to mean the human back and the bird’s wing.”

They may be answered:

This does not imply that they assigned meanings to “the wing of travel” and “the back of the road.” Rather, these expressions were used in a genitive construction with something different from that used in the other expressions—if those other expressions were indeed in a genitive construction. If they were not, an expression in a genitive construction is not the same as a definite expression outside such a construction.

Thus, a definite expression, or one annexed to a particular thing, is not the same as an expression annexed to something else. If someone says “the wing” and “the back,” or says “the bird’s wing” and “the human back,” neither form is the same as “the wing of travel,” “the back of the road,” or “the wing of humility.”

Likewise, when one speaks of the road’s head, back, middle, upper part, and lower part, each has a meaning specific to the road, even if it is not like a human being’s head, back, middle, upper part, and lower part. Similarly, the lower and upper parts of a mountain have meanings specific to it. The same applies to all other nouns in genitive constructions: their meanings are distinguished by what they are annexed to. It is well known that, in their language, an expression formed through fusion, predication, or a genitive construction is not equivalent to an expression without such a construction, whether in grammatical inflection or in meaning. Rather, they distinguish