Note: I have now asked this question on the History Stack Exchange also.
There are at least 33 types of ancient sacrificial, wine, food and water ritual bronze vessels of ancient China, none of which are named 壺.
According to my research the ancient Tang 壺 was a wine vessel (12 types of wine vessels listed above). But seeing as there are so many very precise different kind of ancient vessels, I want to know exactly which one the ancient Tang 壺 is and what it looks like.
For example, I came across this Pot titled 鎏金银嵌宝仿唐壶:
This imitation 唐壶 is very different from the ones posted in the answer below, and on the link I provided before I see that the long spout was a later addition to the pot that was not common previously. So I don't know the EXACT range of styles that the word 壺 encompasses in the Tang Dynasty era.
Also, whereas I want to know the full range of what a 壺 encompasses in the Tang era, I'm particularly interested in the finer 壺 made of jade or gold or etc.
This is a picture of a late 11th century BC altar set of wine vessels (Western Zhou Dynasty, long before the Tang Dynasty, kept at "the Met"). The central vessel is a Zun (尊/樽/鐏), and there are many different kinds of wine vessels including the 斝 and 爵 here pictured. Would all these classify as “壺”, or would some of them only be 杯? I need to know which ones would classify under the “壺” category and which ones wouldn't. Certainly the Zun was still in use during the Tang Dynasty until at least the Song, but would it count as a “壺”?