When an eBay seller uses the word “estate” or “estate sale” in his or her listing, it simply means that they got the item you’re viewing from an auction or house sale (not the same thing as a garage sale). It’s to indicate that something is used.
It’s also implied that the item is vintage and collectible. That’s not always the case, but most sellers do use it in this way. It’s a good keyword for the title of your listing.
Here’s an example of an estate pipe we recently sold:
What does the word “estate” make you think of?