people use it to refer to someone died while others say relatives that are alive??
The key word in what Colleen wrote is "bloodline." In other words, not aunts and uncles. But your great-grandparents (8), great-great grandparents (16), etc., all the way back to either Adam and Eve or some nameless protozoa (depending on what you believe about human origins).
Ancestors are your past bloodline generations that have died. They become ancestors when their estate has been passed down, which only happens after death.
You're ancestors are people in you're family that are in a different generation. Not your immediate family.
I stand corrected. They have died if it's an ancestor.