I'm looking at Byzantine gold solidus's and in their description is 3rd officina, or 8th officina, or 5th..etc. Is this something like the "edition" of a particular solidus? Are some officina's more desireable?
Every coin was handmade, so they were all a little different. Introducing officinae was a way to break down and categorize the coins so the mint didn't release an unorganized mess of assorted coins. It also made quality control easier. EDIT: there are usually very minute differences between officinae, and most collectors don't get into the weeds to really care. For some coins particular officinae are much rarer than others, which can make them more desirable to the right person.
Is there still discussion as to whether an officina could have represented a work shift, rather than a physical workshop?
If it was the case, I envy the workers in Antioch during the time of Constantius II; there were 15 officinae... the work shifts were very short... the guys would have been home early !
RIC VII (Constantine and Licinius) actually gives separate rarity ratings for each different officina, so someone must care. Can't say I'm one of those people, though. And the reality is that this has led to a lot of hyperbolic marketing of coins from this era on eBay.
During some periods the officinae were used to produce different reverse types. I will illustrate with example from the 4 different officinae operating in Emission 9 (Bastien) of Probus from Lugdunum. At this point the officinae were identified by the letters A, B, C and D Martin
Workshop or Atelier if you prefer. I assume this gave the authorities a means of quality control and also allowed them to assess the work of the die cutters and dudes doing the striking of the coins. So if someone screwed up they could go back to the source.
Though atelier can translate to workshop, I believe it is most frequently used to mean the entire mint. For example-- Bastien's series Le monnayage de l 'atelier de Lyon Ferrando's L'atelier monétaire d 'Arles