vehaKna'ani az ba'aretz - and the Kenaanim were then in the land
The Kenaanim, a powerful people, dominated that land at that time. Avraham was afraid of them and this is why we did not hear of his building an altar, i.e. preaching his religion, at that time until G-d appeared to him at Shechem and promised him that his descendants would inherit the land of Kenaan. Then Avraham was no longer afraid and it became clear to him that this was the land that G-d had promised him and this is why the Torah says, "he built an altar to the G-d Who had appeared to him" (v7). This was a way of thanking G-d for this assurance (compare Bereishit Rabbah 39:16) that his descendants would inherit the land. The Kenaanim had arealdy lived in the land since the days of Noach and this made it easy for G-d to dispossess them in due course; they were after all a nation cursed to be slaves and as slaves had no legal claim to any property.
A reason for the word az is that the word is an acrostic composed of aklim zayin (7th climate) [this is a hyperbole for the central region, the words "middle climate" referring to a region devoid of extremes]. It may also be referred to as the land of the fourth, i.e. the central "climate". Concerning this central "climate," Shlomo wrote in Mishlei 31:24, "she gave the belt to the Kenaanim." As is well known, a belt is worn around a person's middle. What Shlomo meant was that this central piece of the earth was given to the Kenaanim on a temporary basis until its true owner, the Jewish people, would be awarded it by G-d on a permanent basis.
Another meaning of the word az in our verse may be connected to the Torah not describing the Kenaanim as "dwelling permanently in the land." The Torah only referred to the Kenaanim as being present in the land. This is in contrast to Bereishit 13:7 where the Torah did use the term yoshev (was dwelling) when describing the tenure of the Kenaanim and the Perizzim in that land. The reason is that in that verse the Torah did not refer to a people which had its inheritance in that land but only to two tribes which had control of it at that time.
There is a celestial force known as "Kenaanim." This is a force from which the 70 nations derive their power on earth as we know from Yehoshua who said to the Yisraelim (at the time when the Yisraelim on the East Bank of the Yarden had built a public altar, something that aroused suspicions of their national and religious secession), "Choose this day which ones you are going to serve, the gods that your forefathers served beyond the Euphrates or those of the Emorim in whose lands you are settled; but I am my household will serve Hashem." We find that the celestial representative of the Egyptian nation is called Mitzrayim by the Torah when we read in Shemot 14:10, "and here Egypt (instead of the Egyptians) was traveling behind them." Had the Torah referred to Egyptian nationals, human beings, the word for "traveling" should have been nose'a'im instead of the singular nose'a.
These concepts which we are familiar with through the study of Kabbalah. Even the scientists of our day agree with these concepts.
We also find that the spiritual force of Israel is referred to as Yisrael. This is the meaning of Tehillim 24:6, "Yaakov who seek Your Presence Selah." The psalmist refers to the spiritual concept "Yisrael" who are distinguished by the virtue of seeking out G-d.
The fact that a prophet or angel has a special name should not be something that surprises you; neither should the fact that the site of the Holy Temple has a special name. This is what the Sages in Bava Batra 75 had in mind when they explained that the verse in Yirmeyahu 23:6, "and this is the name he shall be named: ' YKVK is our Vindicator.'" Even a human being may carry the Name of G-d. Similarly, the city of Yerushalayim bears the Name of G-d as we see from the very last verse in Sefer Yechezkel 48:35, "and the name of the city from that day onwards 'YKVK is there.'" The Talmud suggests to change the vowels under the word shemah (its name) to shammah (there). Similarly, it is not surprising to find unusual sounding names for angels, i.e. G-d's agents.