'Extremity' in the Bible

And they journey from Succoth, and encamp in Etham at the extremity of the wilderness,

And the sons of Israel have eaten the manna forty years, until their coming in unto the land to be inhabited; the manna they have eaten till their coming in unto the extremity of the land of Canaan.

And thou hast made a border for the people round about, saying, Take heed to yourselves, going up into the mount, or coming against its extremity; whoever is coming against the mount is certainly put to death;