veha'aretz hayetah tohu vavohu - and the earth was chaos and void
This is a reference to the raw material which had not yet been properly defined and therefore could not yet be named.
This explanation is analogous to what our Sages have said in Kiddushin 40 "he had second thoughts on what He had thought before." The Torah called this indefinable material tohu. The word bohu, on the other hand, refers to this material once it had been equipped with a distinctive shape and had assumed a definite form.
The word bohu is actually two words comprised of bo hu - something which does have a certain form by which it is identifiable. This is what Yeshayahu had in mind when he said: "He will measure it with a line of chaos and with weights of emptiness." (34:11) The prophet related the word "a line," to the word which described something indefinable, visible but not possessing substance. An artisan envisages a building in his mind's eye before he builds it. The relations of the word is that the stones are the manifestation, the format of the building the artisan had first envisaged.
To sum up the whole passage, "At the beginning G-d created a minute amount of matter out of absolute nothingness. This contained within itself the potential and energy to expand into what we call 'heaven and earth.' After this initial stage of creative activity by G-d the earth had still remained in a chaotic state, matter without separation into shape or form of the four basic raw materials (elements) of the universe, i.e. fire, wind, water and dust." The word ha'aretz includes all these four basic materials the earth is made of. Even thought the material 'afar (dust) is only the last one described in the record of the creation of man, the Torah refers to it first when speaking about eretz which was a minute point. Philosophers called it a "point," [to distinguish between the solar system which appears in constant motion, whereas the earth appears stationary. They viewed the earth as if it were a point surrounded by the planetary system.
Earth was viewed as stationary based on Kohelet 1:4 "and the earth remains in its place forever." This is in contrast to the planets surrounding it which move from place to place and never remain in the same spot. Only a small part of earth is in motion, ever. The reason the planetary system, i.e. shamayim, is called lofty , high, is because the material it is made of is so delicate, so fine, and so pure. Earth, on the other hand, is made of the coarsest, the most opaque material. Once the Torah had begun to discuss the properties of earth it returns its attention to the heaven and lists the other basic raw materials (elements) in their proper order, i.e. fire, wind, and water. (Rabbeinu Bachya)