Genesis 1:10

He called seas: And is it not [all] one sea? Except that the taste of fish that comes up [from the sea] in Akko (Acre) is not the same as the taste of the fish that comes up [from the sea] in Espamia.

And the Lord called the dry (land) the Earth, and the place of the assemblage of waters called He the Seas; and the Lord saw that it was good.

It said "seas" - since there is not [single] sea which encompasses the entire landmass.

AND G-D CALLED THE DRY LAND EARTH. The verse states that the proper name for it would be yabashah (dry land) for as the waters are separated from the sand it becomes dry. However, He called it eretz (earth) as the name which included the four elements created on the first day. The reason for this is that they were all created for the sake of the earth in order that there be a habitation for man, since among the lower creatures no one but man recognizes his Creator. in the Book of Exodus).
And the gathering together of the waters He called ‘yamim’ (seas). It is as if [the word yamim, (seas) combines the two words] yam and mayim (a sea of waters), for the bottom of the ocean is called yam, as it is written, As the waters cover the sea, and likewise, And he took down the sea from off the brazen oxen. It is called “sea” because there was a large gathering of water in it.

AND G-D SAW THAT IT WAS GOOD. This means that their continued existence was by His Will, and the purport is that when He clothed them with this form He desired them to be so and their existence was thus established as I have explained. This conforms to what our Rabbis have said: “Why is it not stated in reference to the work of the second day that it was good? Because the work associated with the waters was not completed until the third day. Therefore on the third day, [the words ki tov — that it was good] are repeated, once in reference to the completion of the work associated with the waters, and once in reference to [the completion of the other work of] that day.”

ליבשה ארץ, as I explained earlier, the “yabashah” is none other than the earth mentioned in verse 1 as הארץ, as well as in many other places.

ויקרא אלוקים ליבשה ארץ, G’d assigned a name which is applicable to the whole also to parts of it. The reason is that the particular part of the “earth” described previously as merely יבשה, is in reality the most important and productive part of the “earth.” (based on Moreh Nevuchim) Isaiah 45,18 already referred to this when he said of earth that לשבת יצרה, “G’d formed it in order that it be populated,” i.e. subterranean earth is of secondary importance, seeing one cannot cultivate it and make it one’s habitat.

ויקרא, up until now this mass of dry land had not qualified for a name, seeing that it had not been visible to the naked eye. The same applies to the waters, which, though they had existed since the first day, had only now been called ימים, oceans. They had previously only been known as תהום, a murky mass of liquid containing some opaque solid particles. The second verse in which we read of these definitions had been written by Moses, had not been said by G’d. What Moses had meant is that at that time there existed something, which in his time was referred to as תהום.
Alternately, we could say that the word תהם is derived from the word תהו. This would be an appropriate description, seeing that in the deep waters there is so much confusion and so little light that everything appears as utter confusion, and none of the creatures in that environment can derive pleasure or satisfaction from their existence. There are such locations in the middle of the ocean where the waters are exceedingly deep and far removed from any of the continents of the earth known as dry land by the Torah. Certain of the scientists have already offered proof that earth, i.e. our lower universe, is a sphere seeing that earth itself exists as part of a much greater sphere, the universe. [remember that in Kimchi’s time before Copernicus, the earth was considered the center of the universe or the galaxy, not the sun, as proven by Copernicus in 1543. Ed.] According to the theory proposed by Kimchi or the scientists of his time, one configuration cannot maintain its individuality if it is within another configuration which is different. [If I understand him correctly, he reasons that the earth being spherical is determined by its position within the larger universe surrounded by orbiting planets, which would collide if earth were not dead center, and equidistant on all sides from all the planets orbiting around it. Ed.]
; In fact, the very place described by scientists as תהום is an area in which ships cannot navigate, nor fish survive. The word תהום is a figure of speech, borrowed from descriptions of places containing deep waters. The name ים, ocean, on the other hand, is a term describing the location of the water, a word which is not a derivative of any other root or noun. It is not an adjective describing the condition of the water. It is not comparable to the name יבשת, which is called thus because it reflects the fact that it consists of material which is dry. It is a noun in its own right. The noun ארץ, on the other hand, is also not derived from an adjective, but a definition in its own right. The word תהום, though a noun, merely describes a large quantity of water, as distinct from the word ים, which may apply even to a very shallow expanse of water, including areas very close to a sandy beach.