Well, you have been here for a fair amount of time, and it seems your collecting specialty is poisons. If you say it's not one, then I'll rule that possibility out. Scent bottle seems to be the consensus here.It’s definitely not a poison. Most likely perfume as everyone else is leaning towards. Being the size and shape, could be designed for travel and not the usual square bottles for the home. I see it had a paper label or at least a spot for one in the front. Cool find as I’ve never seen one before.