Ah, thanks, didn't think to click the pic. Yes, I think it may be a weaver's shuttle. Now you can look up "weaver's shuttle" or "weaver's beam" and see if you get any image similar to yours. Or if you find you have a class in weaving in your area, you could locate the teacher and ask them.
In the meanwhile you could use it to tidy up a long extension cord. I always find I need an extension cord when I only need a few inches.
It is possible that it was a piece of another thing, such as an aisle. A handy grandmother might have also been an artist too. Did she paint any paintings?