What do you call particular bottling of wine?

Interesting question -- there really isn't a term. Each bottle's label has a combination of elements that identify it, including by not limited to: type of wine ( grape variety, year (vintage), location of vineyard. These are the main variables that can vary bottle to bottle and will dictate quality, flavor -- and cost. In theory, you could have bottlings on different days, with identical elements above, and still end up with subtle taste differences. Some high-end bottles will, of course, bear a serial number. Buying a batch in a series will assure that it's all more or less the same wine.