Moreover, where in the Quran, in the Arabic language, or among any of the nations is it stated that everything that can be pointed to, or everything that has a magnitude, is a body? And that anything sharing this characteristic with it is [like] it in its essential nature?

The word jism (body) occurs in the Quran in the words of the Most High:

“He has increased him abundantly in knowledge and stature.” [al-Baqarah: 247]

And in His words:

“When you see them, their bodies impress you.” [al-Munāfiqūn: 4]

The lexicographers have stated that jism means badan (the bodily frame). Al-Jawharī says in his al-Sihāh: “Abū Zayd said: ‘Jism means jasad (the bodily frame), as do jusmān and juthmān.’” He also says: “Al-Asma‘ī said: ‘Jism and jusmān mean jasad.’”

It is well known that those who employ specialized terminology have extended the word jism from this particular meaning to a broader one. They thus call air, the flame of a fire, and other such things bodies, whereas the Arabs do not call these things jism, just as they do not call them jasad or badan.

Furthermore, “body” may mean the bodily frame itself, subsisting in its own right, or it may mean its thickness, as when one says, “This cloth has body.”

Likewise, those who use specialized terminology sometimes intend one of these meanings by “body” and sometimes the other. They distinguish between the mathematical body, abstracted from the substrate called matter and hayūlā (hyle), and the actually existing natural body.

This is discussed at length elsewhere.