When I was coming up with a name for my blog, I decided that ANCESTOR worship implied one individual who a person is spawned from while ANCESTRY implies a worship of not only many individuals but one's ethnicity and heritage, which might also be a religious heritage.
For instance, you hear someone say "I'm of Irish Ancestry," or "I'm Jewish," much more than you hear someone say, "Genghis Khan is my ancestor."
I used the term worship because most genealogists I meet, be they hobbyists working only on their own family lines, or professionals, have a certain drive or passion for their research. You could say they are religious about it.
It is with great pride that people have shown me big scrap books full of pictures of their ancestors. It is with artistry that some of them have hand-drawn the most amazing charts. Each of the individuals they've put on their charts has lived a unique life and has contributed to our being here, even when that contribution was minimal. Lately genealogists are using various genealogy computer software that allow them to upload pictures of documents, pictures, and other artifacts that tell the story of each individual on their chart, and then some. These people are not in their direct blood line but to the left and right of it - their aunts, uncles, nieces, nephews, and their spouses and children, as examples.
Of course, in some cultures, ancestor or ancestry worship is by way of ritual, very much part of life. There are special times of the year, special festivals, to honor the dead. People decorate or visit graves, have a picnic in the cemetery or clean the graves, as a way of showing respect. In American culture the celebration of Halloween has turned a once holy holiday called All Souls, when people prayed for the departed, into a celebration that is sometimes evil. I would rather light a candle as a symbol of eternal life for someone who has passed away.
