Jebus, meaning "hard trodden" or "the waterless hill," was the name of a Canaanite city. It was named from the Jebusites, an ancient people descended from Canaan. Jebus was taken by King David, after which the city became the Israelite capital. Although the city was captured by David, David did not ignore the property rights of the people there. It was from Ornan the Jebusite that David purchased the part of the city that later became known as the Temple Mount.
"David and all Israel went to Jerusalem, which is Jebus"
Even by the time of The Judges, when the Israelites were well established in their Promised Land, Jebus was still held by the Jebusites, and as such, the city that became Jerusalem was avoided by Israelites who called it "the city of a stranger":
"And when they were by Jebus, the day was far spent; and the servant said unto his master, Come, I pray thee, and let us turn in into this city of the Jebusites, and lodge in it."
"And his master said unto him, We will not turn aside hither into the city of a stranger, that is not of the children of Israel; we will pass over to Gibeah." (Judges 19:11-12 KJV)
By the time of King David however, Jebus, although well fortified, was taken by the people of Israel under the lawful authority of God's command.
"Then all Israel gathered themselves to David unto Hebron, saying, Behold, we are thy bone and thy flesh. And moreover in time past, even when Saul was king, thou wast he that leddest out and broughtest in Israel: and The Lord thy God said unto thee, Thou shalt feed my people Israel, and thou shalt be ruler over my people Israel."
"Therefore came all the elders of Israel to the king to Hebron; and David made a covenant with them in Hebron before The Lord; and they anointed David king over Israel, according to the word of The Lord by Samuel."
"And David and all Israel went to Jerusalem, which is Jebus; where the Jebusites were, the inhabitants of the land. And the inhabitants of Jebus said to David, Thou shalt not come hither. Nevertheless David took the castle of Zion, which is the city of David."
"And David said, Whosoever smiteth the Jebusites first shall be chief and captain. So Joab the son of Zeruiah went first up, and was chief."
"And David dwelt in the castle; therefore they called it the city of David. And he built the city round about, even from Millo round about: and Joab repaired the rest of the city. So David waxed greater and greater: for The Lord of hosts was with him." (1 Chronicles 11:1-9 KJV)
Fact Finder: What is the ultimate meaning of "Zion" as mentioned in the verses quoted above?
See The Zion Of The Lord