Apologies for necromancy (if this counts). I imagine these types of bottles might pop up everywhere, and while doing a little bottle research for the Sleepy Hollow Jincan poison bottle I learned quite a bit that might come in handy for others:
Both the round and square bottles are referred to as “clear glass reagent bottles” with “ground glass stoppers.” Ground being the operative stopper term. Giggle’s image search for both of my quoted terms will yield a variety of suppliers.
In the professional bottling world, it seems the square shaped bottles are simply called “square,” while
rectangular bottles will be labeled both “square” or “flat square.” Yes, rectangles are actually flat squares. Maybe it’s a translator thing? The word “rectangle” is almost never used, and “rectangular” doesn’t usually appear until secondary less-professional resale corners of the web. Most people label them “apothecary” bottles. So the term “apothecary bottle ground stopper” may filter out a lot of the modern spice bottles with rubbered stoppers you may not be looking for.
Laboratory bottles with hard 90 corners seem to be rarely produced nowadays, but are common in the diffuser, perfume and liquor bottle categories. For hard corner lab reagent bottles, you’ll have the most luck trolling for vintage resales, though in vintage they may often not include the term “ground,” for the stopper. Queries akin to “medicine bottle glass stopper” yields variety of results you can pare down according to your needs. I found only a rare few modern diffuser or liquor bottles that actually have ground glass stoppers. Decanters, however, see some.
Finally, the mouth of the bottles above are considered “wide,” while “narrow” (smaller) is an alternative in many lab bottle options (presumably for liquids). So a giggle search for a query akin to clear glass wide mouth reagent bottle ground stopper may very well shotgun AND improve your results.
And no, I have found not one modern supplier for a suitably similar jincan bottle. I will have to A) troll vintage or B) chuck accuracy and go full-size liquor bottle. If I do that, you can bet I’m making the jincan drinkable and keeping it backlit on my bar. Next year’s Halloween, baby!