Thanks for the feedback.
Could be a canning jar, could be a product jar, but without embossing, it will be hard to go anywhere...perhaps an old WT catalog might shed some light on the use.
The Red Book of Fruit Jars does have a small section devoted to unmarked jars but I do not see anything similar to this in my copy of Edition #8.
My feeling is your jar is an early 20th century product jar...likely fitted with a label
